Navigation scene analysis systems and methods

ABSTRACT

Techniques are disclosed for systems and methods to provide assisted and/or autonomous navigation for mobile structures. A docking assist system includes a logic device, one or more sensors, one or more actuators/controllers, and modules to interface with users, sensors, actuators, and/or other modules of a mobile structure. The logic device is adapted to receive docking assist parameters from a user interface and perimeter sensor data from a perimeter ranging system mounted to the mobile structure. The logic device determines docking assist control signals based on the docking assist parameters and perimeter sensor data. The logic device may then provide the docking assist control signals to a navigation control system. Control signals and/or other docking assist analysis and/or parameters may be displayed to a user and/or used to adjust a steering actuator, a propulsion system thrust, and/or other operational systems of the mobile structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. ProvisionalPatent Application No. 62/975,746 filed Feb. 12, 2020 and entitled“NAVIGATION SCENE ANALYSIS SYSTEMS AND METHODS, which is herebyincorporated by reference in its entirety.

This application is also a continuation-in-part of InternationalApplication No. PCT/US2019/058958 filed Oct. 30, 2019 and entitled“ASSISTED DOCKING GRAPHICAL USER INTERFACE SYSTEMS AND METHODS,” whichis hereby incorporated by reference in its entirety. InternationalApplication No. PCT/US2019/058958 is a continuation-in-part ofInternational Application No. PCT/US2019/017382 filed Feb. 9, 2019 andentitled “AUTOPILOT INTERFACE SYSTEMS AND METHODS,” which is herebyincorporated by reference in its entirety. International Application No.PCT/US2019/017382 claims priority to and the benefit of U.S. ProvisionalPatent Application No. 62/671,394 filed May 14, 2018 and entitled“AUTOPILOT INTERFACE SYSTEMS AND METHODS,” and U.S. Provisional PatentApplication No. 62/628,905 filed Feb. 9, 2018 and entitled “AUTONOMOUSAND ASSISTED DOCKING SYSTEMS AND METHODS,” which are all herebyincorporated by reference in their entirety.

This application is also a continuation-in-part of U.S. patentapplication Ser. No. 16/533,572 filed Aug. 6, 2019 and entitled“AUTONOMOUS AND ASSISTED DOCKING SYSTEMS AND METHODS,” which is herebyincorporated by reference in its entirety. U.S. patent application Ser.No. 16/533,572 is a continuation-in-part of U.S. patent application Ser.No. 15/620,675 filed Jun. 12, 2017 and entitled “ADAPTIVE AUTOPILOTCONTROL SYSTEMS AND METHODS,” which is a continuation of InternationalPatent Application No. PCT/US2015/068342 filed Dec. 31, 2015 andentitled “ADAPTIVE AUTOPILOT CONTROL SYSTEMS AND METHODS”, which arehereby incorporated by reference in their entirety. U.S. patentapplication Ser. No. 16/533,572 is a continuation of InternationalApplication No. PCT/US2018/037953 filed Jun. 15, 2018 and entitled“AUTONOMOUS AND ASSISTED DOCKING SYSTEMS AND METHODS,” which is herebyincorporated by reference in its entirety. International Application No.PCT/US2018/037953 claims priority to and the benefit of U.S. ProvisionalPatent Application No. 62/628,905 filed Feb. 9, 2018 and entitled“AUTONOMOUS AND ASSISTED DOCKING SYSTEMS AND METHODS,” U.S. ProvisionalPatent Application No. 62/584,718 filed Nov. 10, 2017 and entitled“AUTONOMOUS AND ASSISTED DOCKING SYSTEMS AND METHODS,” and U.S.Provisional Patent Application No. 62/521,346 filed Jun. 16, 2017 andentitled “AUTONOMOUS AND ASSISTED DOCKING SYSTEMS AND METHODS,” whichare all hereby incorporated by reference in their entirety.

This application is also a continuation-in-part of U.S. patentapplication Ser. No. 16/533,598 filed Aug. 6, 2019 and entitled“PERIMETER RANGING SENSOR SYSTEMS AND METHODS,” which is herebyincorporated by reference in its entirety. U.S. patent application Ser.No. 16/533,598 is a continuation of International Application No.PCT/US2018/037954 filed Jun. 15, 2018 and entitled “PERIMETER RANGINGSENSOR SYSTEMS AND METHODS,” which is hereby incorporated by referencein its entirety. International Application No. PCT/US2018/037954 claimspriority to and the benefit of U.S. Provisional Patent Application No.62/628,905 filed Feb. 9, 2018 and entitled “AUTONOMOUS AND ASSISTEDDOCKING SYSTEMS AND METHODS,” U.S. Provisional Patent Application No.62/584,718 filed Nov. 10, 2017 and entitled “AUTONOMOUS AND ASSISTEDDOCKING SYSTEMS AND METHODS,” and U.S. Provisional Patent ApplicationNo. 62/521,346 filed Jun. 16, 2017 and entitled “AUTONOMOUS AND ASSISTEDDOCKING SYSTEMS AND METHODS,” which are all hereby incorporated byreference in their entirety.

TECHNICAL FIELD

One or more embodiments of the invention relate generally to directionalcontrol and more particularly, for example, to systems and methods forassisted and/or fully autonomous docking and/or navigation forwatercraft.

BACKGROUND

Directional control systems are used to provide automated and/orsupplemented control for planes, watercraft, and, more recently,automobiles. Conventional automated directional control systemstypically require a multitude of relatively expensive and purpose-builtsensors that are difficult to retrofit into an existing vehicle andproduce results that are not accurate enough to be used to providereliable docking or parking assist for a vehicle, particularly incrowded conditions and/or while navigational control is complicated byexternal disturbances, such as by wind or water currents. Thus, there isa need for improved docking assist methodologies.

SUMMARY

Techniques are disclosed for systems and methods to provide dockingassist for a mobile structure. In accordance with one or moreembodiments, a docking assist system may include a logic device, amemory, one or more sensors, one or more actuators/controllers, andmodules to interface with users, sensors, actuators, and/or othermodules of a mobile structure. The logic device may be adapted toreceive docking assist parameters for a mobile structure and perimetersensor data from a perimeter ranging system. The logic device may beconfigured to determine docking assist control signals based, at leastin part, on the docking assist parameters and perimeter sensor data. Thedetermined docking assist control signals may be provided to anavigation control system for the mobile structure. These and othercontrol signals may be displayed to a user and/or used to adjust asteering actuator, a propulsion system thrust, and/or other operationalsystems of the mobile structure.

In various embodiments, a docking assist system may include a logicdevice configured to communicate with a user interface and a perimeterranging system mounted to a mobile structure and to provide dockingassist for the mobile structure. The logic device may be configured toreceive docking assist parameters from the user interface and perimetersensor data from the perimeter ranging system; determine one or moredocking assist control signals based, at least in part, on the receiveddocking assist parameters and the received perimeter sensor data; andprovide the one or more docking assist control signals to a navigationcontrol system for the mobile structure.

In some embodiments, a method to provide docking assist for a mobilestructure may include receiving docking assist parameters from a userinterface for the mobile structure and perimeter sensor data from aperimeter ranging system mounted to the mobile structure; determiningone or more docking assist control signals based, at least in part, onthe received docking assist parameters and the received perimeter sensordata; and providing the one or more docking assist control signals to anavigation control system for the mobile structure.

In additional embodiments, a docking assist or more generalizedautopilot system may include a control signal coupling configured tocouple to a control signal line of a manual user interface for a mobilestructure and a logic device configured to communicate with the controlsignal coupling. The logic device may be configured to monitor controlsignals communicated between the manual user interface and a navigationcontrol system for the mobile structure, determine a navigation mode forthe mobile structure, and selectively relay, block, or modify themonitored control signals based, at least in part, on the determinednavigation mode for the mobile structure and the monitored controlsignals. In related embodiments, the logic device may be configured toidentify maneuvering signals generated by the manual user interfacebased, at least in part, on the monitored control signals, determine amaneuvering protocol corresponding to the manual user interface based,at least in part, on the identified maneuvering signals, and selectivelyrelay, block, or modify the monitored control signals based on thedetermined navigation mode for the mobile structure, the monitoredcontrol signals, and the determined maneuvering protocol.

In further embodiments, a method for providing docking and/or autopilotassistance may include monitoring control signals communicated between amanual user interface and a navigation control system for a mobilestructure, identifying maneuvering signals generated by the manual userinterface based, at least in part, on the monitored control signals, anddetermining a maneuvering protocol corresponding to the manual userinterface based, at least in part, on the identified maneuveringsignals. A related method may include monitoring control signalscommunicated between a manual user interface and a navigation controlsystem for a mobile structure, determining a navigation mode for themobile structure, and selectively relaying, blocking, or modifying themonitored control signals based, at least in part, on the determinednavigation mode for the mobile structure and the monitored controlsignals.

In another embodiment, a docking assist or more generalized autopilotsystem may include a logic device configured to communicate with a userinterface and a perimeter ranging system mounted to a mobile structureand to provide docking assist for the mobile structure. The logic devicemay be configured to receive docking assist parameters from the userinterface and perimeter sensor data from the perimeter ranging systemand determine one or more docking assist control signals based, at leastin part, on the received docking assist parameters and the receivedperimeter sensor data.

In another embodiment, a method to provide docking assist or moregeneralized autopiloting for a mobile structure may include receivingdocking assist parameters from a user interface for the mobile structureand perimeter sensor data from a perimeter ranging system mounted to themobile structure and determining one or more docking assist controlsignals based, at least in part, on the received docking assistparameters and the received perimeter sensor data.

The scope of the invention is defined by the claims, which areincorporated into this section by reference. A more completeunderstanding of embodiments of the invention will be afforded to thoseskilled in the art, as well as a realization of additional advantagesthereof, by a consideration of the following detailed description of oneor more embodiments. Reference will be made to the appended sheets ofdrawings that will first be described briefly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a block diagram of a mobile structure including adocking assist system in accordance with an embodiment of thedisclosure.

FIG. 1B illustrates a diagram of a watercraft including a docking assistsystem in accordance with an embodiment of the disclosure.

FIG. 1C illustrates a diagram of a steering sensor/actuator for adocking assist system in accordance with an embodiment of thedisclosure.

FIGS. 1D-E are diagrams illustrating operation of a thrust maneuversystem for a docking assist system in accordance with an embodiment ofthe disclosure.

FIGS. 2A-K show diagrams illustrating various aspects of a perimeterranging system for a docking assist system in accordance with anembodiment of the disclosure.

FIGS. 3A-E show display views and target docking tracks for a dockingassist system in accordance with an embodiment of the disclosure.

FIGS. 4-11 illustrate flow diagrams of control loops to provide dockingassist in accordance with embodiments of the disclosure.

FIG. 12 illustrates plots of various control signals for a dockingassist system, in accordance with embodiments of the disclosure.

FIGS. 13-21 illustrate flow diagrams of control loops to provide dockingassist in accordance with embodiments of the disclosure.

FIGS. 22-23 illustrate processes to provide docking assist in accordancewith embodiments of the disclosure.

FIG. 24 illustrates plots of various simulation parameters and controlsignals for a docking assist system, in accordance with embodiments ofthe disclosure.

FIG. 25 illustrates a flow diagram of a process to provide dockingassist for a mobile structure in accordance with an embodiment of thedisclosure.

FIG. 26 illustrates a block diagram of a docking assist systemintegrated with a thrust maneuver system in accordance with anembodiment of the disclosure.

FIGS. 27-29 illustrate null zone transfer functions in accordance withembodiments of the disclosure.

FIG. 30 illustrates a flow diagram of a process to provide null zonecompensation for a docking assist system in accordance with anembodiment of the disclosure.

FIG. 31 illustrates a flow diagram of a process to determine amaneuvering protocol for a navigation control system in accordance withan embodiment of the disclosure.

FIG. 32 illustrates a flow diagram of a process to provide autonomousand/or assisted navigational control for a mobile structure inaccordance with an embodiment of the disclosure.

FIG. 33 illustrates a graph of a propulsion system thrust as a functionof demand in accordance with an embodiment of the disclosure.

FIG. 34 illustrates a flow diagram of control loops to providelinearized response from a propulsion system in accordance with anembodiment of the disclosure.

FIG. 35 illustrates a graph of a time domain transfer functionrepresentative of a modulated propulsion system thrust as a function ofdemand in accordance with an embodiment of the disclosure.

FIGS. 36A-B illustrate a flow diagram of a process to provide navigationscene analysis for autonomous and/or assisted navigational control for amobile structure in accordance with an embodiment of the disclosure.

FIG. 37 illustrates a scene analysis map associated with navigationscene analysis for autonomous and/or assisted navigational control for amobile structure in accordance with an embodiment of the disclosure.

FIG. 38 illustrates a scene analysis map associated with navigationscene analysis for autonomous and/or assisted navigational control for amobile structure in accordance with an embodiment of the disclosure.

FIG. 39 illustrates a scene analysis map associated with navigationscene analysis for autonomous and/or assisted navigational control for amobile structure in accordance with an embodiment of the disclosure.

FIG. 40 illustrates a scene analysis map associated with navigationscene analysis for autonomous and/or assisted navigational control for amobile structure in accordance with an embodiment of the disclosure.

FIG. 41 illustrates a scene analysis map associated with navigationscene analysis for autonomous and/or assisted navigational control for amobile structure in accordance with an embodiment of the disclosure.

FIGS. 42A-B illustrate a software architecture to provide navigationscene analysis for autonomous and/or assisted navigational control for amobile structure in accordance with an embodiment of the disclosure.

FIG. 43 illustrates pushback thrust vectors based on navigation sceneanalysis for autonomous and/or assisted navigational control for amobile structure in accordance with an embodiment of the disclosure.

Embodiments of the invention and their advantages are best understood byreferring to the detailed description that follows. It should beappreciated that like reference numerals are used to identify likeelements illustrated in one or more of the figures.

DETAILED DESCRIPTION

In accordance with various embodiments of the present disclosure,docking assist systems and methods may provide assisted and/or fullautomated docking and/or directional control for mobile structures thatis substantially more reliable and accurate than conventional systemsacross a wide variety of types of structures and environmentalconditions. Embodiments disclosed herein address deficiencies ofconventional methodologies with respect to selection of target dockingposition and orientation and/or target docking track, perimetermonitoring, navigation hazard avoidance, user control of dockingapproach, and adaptive navigational control of a mobile structure duringassisted and/or autonomous docking.

One or more embodiments of the described docking assist system mayadvantageously include a controller and one or more of an orientationsensor, a gyroscope, an accelerometer, a position sensor, a speedsensor, and/or a steering sensor/actuator providing measurements of anorientation, position, acceleration, speed, and/or steering angle of themobile structure. In some embodiments, the controller may be adapted toexecute one or more control loops to model and/or control navigation ofthe mobile structure during a docking assist. The system may beconfigured to receive measured or modeled sensor signals and providedocking assist control signals, as described herein. For example, thesensors may be mounted to or within the mobile structure (e.g., awatercraft, aircraft, motor vehicle, and/or other mobile structure), ormay be integrated with the controller. Various embodiments of thepresent disclosure may be configured to automatically coordinatesteering actuator operations with various orientation and/or positionmeasurements to provide relatively high quality and low noisedirectional control.

As an example, FIG. 1A illustrates a block diagram of system 100 inaccordance with an embodiment of the disclosure. In various embodiments,system 100 may be adapted to provide docking assist for a particularmobile structure 101. Docking assist of a mobile structure may refer tofully automated docking of the mobile structure, for example, or toassisted docking of the mobile structure, where the system compensatesfor detected navigation hazards (e.g., such as an approaching dock)and/or various environmental disturbances (e.g., such as a cross wind ora water current) while assisting direct user control of mobile structuremaneuvers. Such docking assist may include control of yaw, yaw rate,and/or linear velocity of mobile structure 101. In some embodiments,system 100 may be adapted to measure an orientation, a position, and/ora velocity of mobile structure 101, a relative or absolute wind, and/ora water current. System 100 may then use these measurements to controloperation of mobile structure 101, such as controlling elements ofnavigation control system 190 (e.g., steering actuator 150, propulsionsystem 170, and/or optional thrust maneuver system 172) to steer ororient mobile structure 101 according to a desired heading ororientation, such as heading angle 107, for example.

In the embodiment shown in FIG. 1A, system 100 may be implemented toprovide docking assist for a particular type of mobile structure 101,such as a drone, a watercraft, an aircraft, a robot, a vehicle, and/orother types of mobile structures. In one embodiment, system 100 mayinclude one or more of a sonar system 110, a user interface 120, acontroller 130, an orientation sensor 140, a speed sensor 142, agyroscope/accelerometer 144, a global navigation satellite system (GNSS)146, a perimeter ranging system 148, a steering sensor/actuator 150, apropulsion system 170, a thrust maneuver system 172, and one or moreother sensors and/or actuators used to sense and/or control a state ofmobile structure 101, such as other modules 180. In some embodiments,one or more of the elements of system 100 may be implemented in acombined housing or structure that can be coupled to mobile structure101 and/or held or carried by a user of mobile structure 101.

Directions 102, 103, and 104 describe one possible coordinate frame ofmobile structure 101 (e.g., for headings or orientations measured byorientation sensor 140 and/or angular velocities and accelerationsmeasured by gyroscope/accelerometer 144). As shown in FIG. 1A, direction102 illustrates a direction that may be substantially parallel to and/oraligned with a longitudinal axis of mobile structure 101, direction 103illustrates a direction that may be substantially parallel to and/oraligned with a lateral axis of mobile structure 101, and direction 104illustrates a direction that may be substantially parallel to and/oraligned with a vertical axis of mobile structure 101, as describedherein. For example, a roll component of motion of mobile structure 101may correspond to rotations around direction 102, a pitch component maycorrespond to rotations around direction 103, and a yaw component maycorrespond to rotations around direction 104.

Heading angle 107 may correspond to the angle between a projection of areference direction 106 (e.g., the local component of the Earth'smagnetic field) onto a horizontal plane (e.g., referenced to agravitationally defined “down” vector local to mobile structure 101) anda projection of direction 102 onto the same horizontal plane. In someembodiments, the projection of reference direction 106 onto a horizontalplane (e.g., referenced to a gravitationally defined “down” vector) maybe referred to as Magnetic North. In various embodiments, MagneticNorth, a “down” vector, and/or various other directions, positions,and/or fixed or relative reference frames may define an absolutecoordinate frame, for example, where directional measurements referencedto an absolute coordinate frame may be referred to as absolutedirectional measurements (e.g., an “absolute” orientation).

In some embodiments, directional measurements may initially bereferenced to a coordinate frame of a particular sensor (e.g., a sonartransducer assembly or module of sonar system 110) and be transformed(e.g., using parameters for one or more coordinate frametransformations) to be referenced to an absolute coordinate frame and/ora coordinate frame of mobile structure 101. In various embodiments, anabsolute coordinate frame may be defined and/or correspond to acoordinate frame with one or more undefined axes, such as a horizontalplane local to mobile structure 101 referenced to a local gravitationalvector but with an unreferenced and/or undefined yaw reference (e.g., noreference to Magnetic North).

Sonar system 110 may be implemented with one or more electrically and/ormechanically coupled controllers, transmitters, receivers, transceivers,signal processing logic devices, autonomous power systems, variouselectrical components, transducer elements of various shapes and sizes,multichannel transducers/transducer modules, transducer assemblies,assembly brackets, transom brackets, and/or various actuators adapted toadjust orientations of any of the components of sonar system 110, asdescribed herein. Sonar system 110 may be configured to emit one,multiple, or a series of acoustic beams, receive corresponding acousticreturns, and convert the acoustic returns into sonar data and/orimagery, such as bathymetric data, water depth, water temperature, watercolumn/volume debris, bottom profile, and/or other types of sonar data.Sonar system 110 may be configured to provide such data and/or imageryto user interface 120 for display to a user, for example, or tocontroller 130 for additional processing, as described herein.

For example, in various embodiments, sonar system 110 may be implementedand/or operated according to any one or combination of the systems andmethods described in U.S. Provisional Patent Application 62/005,838filed May 30, 2014 and entitled “MULTICHANNEL SONAR SYSTEMS ANDMETHODS”, U.S. Provisional Patent Application 61/943,170 filed Feb. 21,2014 and entitled “MODULAR SONAR TRANSDUCER ASSEMBLY SYSTEMS ANDMETHODS”, and/or U.S. Provisional Patent Application 62/087,189 filedDec. 3, 2014 and entitled “AUTONOMOUS SONAR SYSTEMS AND METHODS”, eachof which are hereby incorporated by reference in their entirety. Inother embodiments, sonar system 110 may be implemented according toother sonar system arrangements that can be used to detect objectswithin a water column and/or a floor of a body of water.

User interface 120 may be implemented as one or more of a display, atouch screen, a keyboard, a mouse, a joystick, a knob, a steering wheel,a ship's wheel or helm, a yoke, and/or any other device capable ofaccepting user input and/or providing feedback to a user. For example,in some embodiments, user interface 120 may be implemented and/oroperated according to any one or combination of the systems and methodsdescribed in U.S. Provisional Patent Application 62/069,961 filed Oct.29, 2014 and entitled “PILOT DISPLAY SYSTEMS AND METHODS”, which ishereby incorporated by reference in its entirety.

In various embodiments, user interface 120 may be adapted to provideuser input (e.g., as a type of signal and/or sensor information) toother devices of system 100, such as controller 130. User interface 120may also be implemented with one or more logic devices that may beadapted to execute instructions, such as software instructions,implementing any of the various processes and/or methods describedherein. For example, user interface 120 may be adapted to formcommunication links, transmit and/or receive communications (e.g.,sensor signals, control signals, sensor information, user input, and/orother information), determine various coordinate frames and/ororientations, determine parameters for one or more coordinate frametransformations, and/or perform coordinate frame transformations, forexample, or to perform various other processes and/or methods describedherein.

In some embodiments, user interface 120 may be adapted to accept userinput, for example, to form a communication link, to select a particularwireless networking protocol and/or parameters for a particular wirelessnetworking protocol and/or wireless link (e.g., a password, anencryption key, a MAC address, a device identification number, a deviceoperation profile, parameters for operation of a device, and/or otherparameters), to select a method of processing sensor signals todetermine sensor information, to adjust a position and/or orientation ofan articulated sensor, and/or to otherwise facilitate operation ofsystem 100 and devices within system 100. Once user interface 120accepts a user input, the user input may be transmitted to other devicesof system 100 over one or more communication links.

In one embodiment, user interface 120 may be adapted to receive a sensoror control signal (e.g., from orientation sensor 140 and/or steeringsensor/actuator 150) over communication links formed by one or moreassociated logic devices, for example, and display sensor and/or otherinformation corresponding to the received sensor or control signal to auser. In related embodiments, user interface 120 may be adapted toprocess sensor and/or control signals to determine sensor and/or otherinformation. For example, a sensor signal may include an orientation, anangular velocity, an acceleration, a speed, and/or a position of mobilestructure 101 and/or other elements of system 100. In such embodiments,user interface 120 may be adapted to process the sensor signals todetermine sensor information indicating an estimated and/or absoluteroll, pitch, and/or yaw (attitude and/or rate), and/or a position orseries of positions of mobile structure 101 and/or other elements ofsystem 100, for example, and display the sensor information as feedbackto a user.

In one embodiment, user interface 120 may be adapted to display a timeseries of various sensor information and/or other parameters as part ofor overlaid on a graph or map, which may be referenced to a positionand/or orientation of mobile structure 101 and/or other element ofsystem 100. For example, user interface 120 may be adapted to display atime series of positions, headings, and/or orientations of mobilestructure 101 and/or other elements of system 100 overlaid on ageographical map, which may include one or more graphs indicating acorresponding time series of actuator control signals, sensorinformation, and/or other sensor and/or control signals.

In some embodiments, user interface 120 may be adapted to accept userinput including a user-defined target heading, waypoint, route, and/ororientation for an element of system 100, for example, and to generatecontrol signals for navigation control system 190 to cause mobilestructure 101 to move according to the target heading, waypoint, route,track, and/or orientation. In other embodiments, user interface 120 maybe adapted to accept user input modifying a control loop parameter ofcontroller 130, for example, or selecting a responsiveness of controller130 in controlling a direction (e.g., through application of aparticular steering angle) of mobile structure 101.

For example, a responsiveness setting may include selections ofPerformance (e.g., fast response), Cruising (medium response), Economy(slow response), and Docking responsiveness, where the differentsettings are used to choose between a more pronounced and immediatesteering response (e.g., a faster control loop response) or reducedsteering actuator activity (e.g., a slower control loop response). Insome embodiments, a responsiveness setting may correspond to a maximumdesired lateral acceleration during a turn. In such embodiments, theresponsiveness setting may modify a gain, a deadband, a limit on anoutput, a bandwidth of a filter, and/or other control loop parameters ofcontroller 130, as described herein. For docking responsiveness, controlloop responsiveness may be fast and coupled with relatively low maximumacceleration limits.

In further embodiments, user interface 120 may be adapted to accept userinput including a user-defined target attitude, orientation, and/orposition for an actuated device (e.g., sonar system 110) associated withmobile structure 101, for example, and to generate control signals foradjusting an orientation and/or position of the actuated deviceaccording to the target attitude, orientation, and/or position. Moregenerally, user interface 120 may be adapted to display sensorinformation to a user, for example, and/or to transmit sensorinformation and/or user input to other user interfaces, sensors, orcontrollers of system 100, for instance, for display and/or furtherprocessing.

Controller 130 may be implemented as any appropriate logic device (e.g.,processing device, microcontroller, processor, application specificintegrated circuit (ASIC), field programmable gate array (FPGA), memorystorage device, memory reader, or other device or combinations ofdevices) that may be adapted to execute, store, and/or receiveappropriate instructions, such as software instructions implementing acontrol loop for controlling various operations of navigation controlsystem 190, mobile structure 101, and/or other elements of system 100,for example. Such software instructions may also implement methods forprocessing sensor signals, determining sensor information, providinguser feedback (e.g., through user interface 120), querying devices foroperational parameters, selecting operational parameters for devices, orperforming any of the various operations described herein (e.g.,operations performed by logic devices of various devices of system 100).

In addition, a machine readable medium may be provided for storingnon-transitory instructions for loading into and execution by controller130. In these and other embodiments, controller 130 may be implementedwith other components where appropriate, such as volatile memory,non-volatile memory, one or more interfaces, and/or various analogand/or digital components for interfacing with devices of system 100.For example, controller 130 may be adapted to store sensor signals,sensor information, parameters for coordinate frame transformations,calibration parameters, sets of calibration points, and/or otheroperational parameters, over time, for example, and provide such storeddata to a user using user interface 120. In some embodiments, controller130 may be integrated with one or more user interfaces (e.g., userinterface 120) and/or may share a communication module or modules.

As noted herein, controller 130 may be adapted to execute one or morecontrol loops to model or provide device control, steering control(e.g., using navigation control system 190) and/or performing othervarious operations of mobile structure 101 and/or system 100. In someembodiments, a control loop may include processing sensor signals and/orsensor information in order to control one or more operations of mobilestructure 101 and/or system 100.

For example, controller 130 may be adapted to receive a measured heading107 of mobile structure 101 from orientation sensor 140, a measuredsteering rate (e.g., a measured yaw rate, in some embodiments) fromgyroscope/accelerometer 144, a measured speed from speed sensor 142, ameasured position or series of absolute and/or relative positions fromGNSS 146, a measured steering angle from steering sensor/actuator 150,perimeter sensor data from perimeter ranging system 148, and/or a userinput from user interface 120. In some embodiments, a user input mayinclude a target heading 106, for example, an absolute position and/orwaypoint (e.g., from which target heading 106 may be derived), and/orone or more other control loop parameters. In further embodiments,controller 130 may be adapted to determine a steering demand or othercontrol signal for navigation control system 190 based on one or more ofthe received sensor signals, including the user input, and provide thesteering demand/control signal to steering sensor/actuator 150 and/ornavigation control system 190.

In some embodiments, a control loop may include a nominal vehiclepredictor used to produce a feedback signal corresponding to an averageor nominal vehicle/mobile structure rather than one specific to mobilestructure 101. Such feedback signal may be used to adjust or correctcontrol signals, as described herein. In some embodiments, a controlloop may include one or more vehicle dynamics modules corresponding toactual vehicles, for example, that may be used to implement an adaptivealgorithm for training various control loop parameters, such asparameters for a nominal vehicle predictor, without necessitatingreal-time control of an actual mobile structure.

Orientation sensor 140 may be implemented as one or more of a compass,float, accelerometer, and/or other device capable of measuring anorientation of mobile structure 101 (e.g., magnitude and direction ofroll, pitch, and/or yaw, relative to one or more reference orientationssuch as gravity and/or Magnetic North) and providing such measurementsas sensor signals that may be communicated to various devices of system100. In some embodiments, orientation sensor 140 may be adapted toprovide heading measurements for mobile structure 101. In otherembodiments, orientation sensor 140 may be adapted to provide a pitch,pitch rate, roll, roll rate, yaw, and/or yaw rate for mobile structure101 (e.g., using a time series of orientation measurements). In suchembodiments, controller 130 may be configured to determine a compensatedyaw rate based on the provided sensor signals. In various embodiments, ayaw rate and/or compensated yaw rate may be approximately equal to asteering rate of mobile structure 101. Orientation sensor 140 may bepositioned and/or adapted to make orientation measurements in relationto a particular coordinate frame of mobile structure 101, for example.

Speed sensor 142 may be implemented as an electronic pitot tube, meteredgear or wheel, water speed sensor, wind speed sensor, a wind velocitysensor (e.g., direction and magnitude) and/or other device capable ofmeasuring or determining a linear speed of mobile structure 101 (e.g.,in a surrounding medium and/or aligned with a longitudinal axis ofmobile structure 101) and providing such measurements as sensor signalsthat may be communicated to various devices of system 100. In someembodiments, speed sensor 142 may be adapted to provide a velocity of asurrounding medium relative to sensor 142 and/or mobile structure 101.For example, speed sensor 142 may be configured to provide an absoluteor relative wind velocity or water current velocity impacting mobilestructure 101. In various embodiments, system 100 may include multipleembodiments of speed sensor 142, such as one wind velocity sensor andone water current velocity sensor.

Gyroscope/accelerometer 144 may be implemented as one or more electronicsextants, semiconductor devices, integrated chips, accelerometersensors, accelerometer sensor systems, or other devices capable ofmeasuring angular velocities/accelerations and/or linear accelerations(e.g., direction and magnitude) of mobile structure 101 and providingsuch measurements as sensor signals that may be communicated to otherdevices of system 100 (e.g., user interface 120, controller 130). Insome embodiments, gyroscope/accelerometer 144 may be adapted todetermine pitch, pitch rate, roll, roll rate, yaw, yaw rate, compensatedyaw rate, an absolute speed, and/or a linear acceleration rate of mobilestructure 101. Thus, gyroscope/accelerometer 144 may be adapted toprovide a measured heading, a measured steering rate, and/or a measuredspeed for mobile structure 101. In some embodiments,gyroscope/accelerometer 144 may provide pitch rate, roll rate, yaw rate,and/or a linear acceleration of mobile structure 101 to controller 130and controller 130 may be adapted to determine a compensated yaw ratebased on the provided sensor signals. Gyroscope/accelerometer 144 may bepositioned and/or adapted to make such measurements in relation to aparticular coordinate frame of mobile structure 101, for example. Invarious embodiments, gyroscope/accelerometer 144 may be implemented in acommon housing and/or module to ensure a common reference frame or aknown transformation between reference frames.

GNSS 146 may be implemented as a global positioning satellite receiverand/or other device capable of determining an absolute and/or relativeposition of mobile structure 101 based on wireless signals received fromspace-born and/or terrestrial sources, for example, and capable ofproviding such measurements as sensor signals that may be communicatedto various devices of system 100. In some embodiments, GNSS 146 may beadapted to determine and/or estimate a velocity, speed, and/or yaw rateof mobile structure 101 (e.g., using a time series of positionmeasurements), such as an absolute velocity and/or a yaw component of anangular velocity of mobile structure 101. In various embodiments, one ormore logic devices of system 100 may be adapted to determine acalculated speed of mobile structure 101 and/or a computed yaw componentof the angular velocity from such sensor information. GNSS 146 may alsobe used to estimate a relative wind velocity or a water currentvelocity, for example, using a time series of position measurementswhile mobile structure is otherwise lacking powered navigation control.

Perimeter ranging system 148 may be adapted to detect navigation hazardswithin a monitoring perimeter of mobile structure 101 (e.g., within apreselected or predetermined range of a perimeter of mobile structure101) and measure ranges to the detected navigation hazards (e.g., theclosest approach distance between a perimeter of mobile structure 101and a detected navigation hazard) and/or relative velocities of thedetected navigation hazards. In some embodiments, perimeter rangingsystem 148 may be implemented by one or more ultrasonic sensor arraysdistributed along the perimeter of mobile structure 101, radar systems,short range radar systems (e.g., including radar arrays configured todetect and/or range objects between a few centimeters and 10 s of metersfrom a perimeter of mobile structure 101), visible spectrum and/orinfrared/thermal imaging modules or cameras, stereo cameras, LIDARsystems, combinations of these, and/or other perimeter ranging systemsconfigured to provide relatively fast and accurate perimeter sensor data(e.g., so as to accommodate suddenly changing navigation conditions dueto external disturbances such as tide and wind loadings on mobilestructure 101). An embodiment of perimeter ranging system 148implemented by cameras mounted to watercraft is discussed with referenceto FIGS. 2A-I.

Navigation hazards, as used herein, may include an approaching dock ortie down post, other vehicles, floating debris, mooring lines, swimmersor water life, and/or other navigation hazards large and/or solid enoughto damage mobile structure 101, for example, or that require their ownsafety perimeter due to regulation, safety, or other concerns. As such,in some embodiments, perimeter ranging system 148 and/or controller 130may be configured to differentiate types of navigation hazards and/orobjects or conditions that do not present a navigation hazard, such asseaweed, pollution slicks, relatively small floating debris (e.g.,depending on a relative speed of the floating debris), and/or othernon-hazardous but detectable objects.

Steering sensor/actuator 150 may be adapted to physically adjust aheading of mobile structure 101 according to one or more controlsignals, user inputs, and/or stabilized attitude estimates provided by alogic device of system 100, such as controller 130. Steeringsensor/actuator 150 may include one or more actuators and controlsurfaces (e.g., a rudder or other type of steering mechanism) of mobilestructure 101, and may be adapted to sense and/or physically adjust thecontrol surfaces to a variety of positive and/or negative steeringangles/positions.

For example, FIG. 1C illustrates a diagram of a steering sensor/actuatorfor a docking assist system in accordance with an embodiment of thedisclosure. As shown in FIG. 1C, rear portion 101C of mobile structure101 includes steering sensor/actuator 150 configured to sense a steeringangle of rudder 152 and/or to physically adjust rudder 152 to a varietyof positive and/or negative steering angles, such as a positive steeringangle α measured relative to a zero steering angle direction (e.g.,designated by a dashed line 134). In various embodiments, steeringsensor/actuator 150 may be implemented with a steering actuator anglelimit (e.g., the positive limit is designated by an angle β and a dashedline 136 in FIG. 1), and/or a steering actuator rate limit “R”.

As described herein, a steering actuator rate limit may be a limit ofhow quickly steering sensor/actuator 150 can change a steering angle ofa steering mechanism (e.g., rudder 132), and, in some embodiments, suchsteering actuator rate limit may vary depending on a speed of mobilestructure 101 along heading 104 (e.g., a speed of a ship relative tosurrounding water, or of a plane relative to a surrounding air mass). Infurther embodiments, a steering actuator rate limit may vary dependingon whether steering sensor/actuator 150 is turning with (e.g., anincreased steering actuator rate limit) or turning against (e.g., adecreased steering actuator rate limit) a prevailing counteractingforce, such as a prevailing current (e.g., a water and/or air current).A prevailing current may be determined from sensor signals provided byorientation sensor 140, gyroscope/accelerometer 142, speed sensor 144,and/or GNSS 146, for example.

In various embodiments, steering sensor/actuator 150 may be implementedas a number of separate sensors and/or actuators, for example, to senseand/or control one or more steering mechanisms substantiallysimultaneously, such as one or more rudders, elevators, and/orautomobile steering mechanisms, for example. In some embodiments,steering sensor/actuator 150 may include one or more sensors and/oractuators adapted to sense and/or adjust a propulsion force (e.g., apropeller speed and/or an engine rpm) of mobile structure 101, forexample, to effect a particular docking assist maneuver (e.g., to meet aparticular steering demand within a particular period of time), forinstance, or to provide a safety measure (e.g., an engine cut-off and/orreduction in mobile structure speed).

In some embodiments, rudder 152 (e.g., a steering mechanism) may beimplemented as one or more control surfaces and/or conventional rudders,one or more directional propellers and/or vector thrusters (e.g.,directional water jets), a system of fixed propellers and/or thrustersthat can be powered at different levels and/or reversed to effect asteering rate of mobile structure 101, and/or other types or combinationof types of steering mechanisms appropriate for mobile structure 101. Inembodiments where rudder 152 is implemented, at least in part, as asystem of fixed propellers and/or thrusters, steering angle α mayrepresent an effective and/or expected steering angle based on, forexample, characteristics of mobile structure 101, the system of fixedpropellers and/or thrusters (e.g., their position on mobile structure101), and/or control signals provided to steering sensor/actuator 150.An effective and/or expected steering angle α may be determined bycontroller 130 according to a pre-determined algorithm, for example, orthrough use of an adaptive algorithm for training various control loopparameters characterizing the relationship of steering angle α to, forinstance, power levels provided to the system of fixed propellers and/orthrusters and/or control signals provided by controller 130, asdescribed herein.

Propulsion system 170 may be implemented as a propeller, turbine, orother thrust-based propulsion system, a mechanical wheeled and/ortracked propulsion system, a sail-based propulsion system, and/or othertypes of propulsion systems that can be used to provide motive force tomobile structure 101. In some embodiments, propulsion system 170 may benon-articulated, for example, such that the direction of motive forceand/or thrust generated by propulsion system 170 is fixed relative to acoordinate frame of mobile structure 101. Non-limiting examples ofnon-articulated propulsion systems include, for example, an inboardmotor for a watercraft with a fixed thrust vector, for example, or afixed aircraft propeller or turbine. In other embodiments, propulsionsystem 170 may be articulated, for example, and/or may be coupled toand/or integrated with steering sensor/actuator 150, such that thedirection of generated motive force and/or thrust is variable relativeto a coordinate frame of mobile structure 101. Non-limiting examples ofarticulated propulsion systems include, for example, an outboard motorfor a watercraft, an inboard motor for a watercraft with a variablethrust vector/port (e.g., used to steer the watercraft), a sail, or anaircraft propeller or turbine with a variable thrust vector, forexample. As such, in some embodiments, propulsion system 170 may beintegrated with steering sensor/actuator 150.

Optional thrust maneuver system 172 may be adapted to physically adjusta position, orientation, and/or linear and/or angular velocity of mobilestructure 101 according to one or more control signals and/or userinputs provided by a logic device of system 100, such as controller 130.Thrust maneuver system 172 may be implemented as one or more directionalpropellers and/or vector thrusters (e.g., directional water jets),and/or a system of fixed propellers and/or thrusters coupled to mobilestructure 101 that can be powered at different levels and/or reversed tomaneuver mobile structure 101 according to a desired linear and/orangular velocity. For example, FIGS. 1D-E are diagrams illustratingoperation of a thrust maneuver system for a docking assist system inaccordance with an embodiment of the disclosure. As shown in diagram100D-1 of FIG. 1D, joystick user interface 120 may be moved laterally byuser input to produce the corresponding lateral velocity for mobilestructure 101 shown in diagram 100D-2. Similarly, as shown in diagram100E-1 of FIG. 1E, joystick user interface 120 may be rotated clockwiseby user input to produce the corresponding clockwise angular velocityfor mobile structure 101 shown in diagram 100E-2.

Other modules 180 may include other and/or additional sensors,actuators, communications modules/nodes, and/or user interface devicesused to provide additional environmental information of mobile structure101, for example. In some embodiments, other modules 180 may include ahumidity sensor, a wind and/or water temperature sensor, a barometer, aradar system, a visible spectrum camera, an infrared camera, and/orother environmental sensors providing measurements and/or other sensorsignals that can be displayed to a user and/or used by other devices ofsystem 100 (e.g., controller 130) to provide operational control ofmobile structure 101 and/or system 100 that compensates forenvironmental conditions, such as wind speed and/or direction, swellspeed, amplitude, and/or direction, and/or an object in a path of mobilestructure 101, for example. In some embodiments, other modules 180 mayinclude one or more actuated and/or articulated devices (e.g.,spotlights, visible and/or IR cameras, radars, sonars, and/or otheractuated devices) coupled to mobile structure 101, where each actuateddevice includes one or more actuators adapted to adjust an orientationof the device, relative to mobile structure 101, in response to one ormore control signals (e.g., provided by controller 130).

In general, each of the elements of system 100 may be implemented withany appropriate logic device (e.g., processing device, microcontroller,processor, application specific integrated circuit (ASIC), fieldprogrammable gate array (FPGA), memory storage device, memory reader, orother device or combinations of devices) that may be adapted to execute,store, and/or receive appropriate instructions, such as softwareinstructions implementing any of the methods described herein, forexample, including for transmitting and/or receiving communications,such as sensor signals, sensor information, and/or control signals,between one or more devices of system 100. In various embodiments, suchmethod may include instructions for forming one or more communicationlinks between various devices of system 100.

In addition, one or more machine readable mediums may be provided forstoring non-transitory instructions for loading into and execution byany logic device implemented with one or more of the devices of system100. In these and other embodiments, the logic devices may beimplemented with other components where appropriate, such as volatilememory, non-volatile memory, and/or one or more interfaces (e.g.,inter-integrated circuit (I2C) interfaces, mobile industry processorinterfaces (MIPI), joint test action group (JTAG) interfaces (e.g., IEEE1149.1 standard test access port and boundary-scan architecture),controller area network (CAN) bus interfaces, and/or other interfaces,such as an interface for one or more antennas, or an interface for aparticular type of sensor).

Each of the elements of system 100 may be implemented with one or moreamplifiers, modulators, phase adjusters, beamforming components, digitalto analog converters (DACs), analog to digital converters (ADCs),various interfaces, antennas, transducers, and/or other analog and/ordigital components enabling each of the devices of system 100 totransmit and/or receive signals, for example, in order to facilitatewired and/or wireless communications between one or more devices ofsystem 100. Such components may be integrated with a correspondingelement of system 100, for example. In some embodiments, the same orsimilar components may be used to perform one or more sensormeasurements, as described herein.

Sensor signals, control signals, and other signals may be communicatedamong elements of system 100 using a variety of wired and/or wirelesscommunication techniques, including voltage signaling, Ethernet, WiFi,Bluetooth, Zigbee, Xbee, Micronet, CAN bus, or other medium and/or shortrange wired and/or wireless networking protocols and/or implementations,for example. In such embodiments, each element of system 100 may includeone or more modules supporting wired, wireless, and/or a combination ofwired and wireless communication techniques.

In some embodiments, various elements or portions of elements of system100 may be integrated with each other, for example, or may be integratedonto a single printed circuit board (PCB) to reduce system complexity,manufacturing costs, power requirements, coordinate frame errors, and/ortiming errors between the various sensor measurements. For example,gyroscope/accelerometer 144 and controller 130 may be configured toshare one or more components, such as a memory, a logic device, acommunications module, and/or other components, and such sharing may actto reduce and/or substantially eliminate such timing errors whilereducing overall system complexity and/or cost.

Each element of system 100 may include one or more batteries,capacitors, or other electrical power storage devices, for example, andmay include one or more solar cell modules or other electrical powergenerating devices (e.g., a wind or water-powered turbine, or agenerator producing electrical power from motion of one or more elementsof system 100). In some embodiments, one or more of the devices may bepowered by a power source for mobile structure 101, using one or morepower leads. Such power leads may also be used to support one or morecommunication techniques between elements of system 100.

In various embodiments, a logic device of system 100 (e.g., oforientation sensor 140 and/or other elements of system 100) may beadapted to determine parameters (e.g., using signals from variousdevices of system 100) for transforming a coordinate frame of otherelements of system 100 to/from a coordinate frame of mobile structure101, at-rest and/or in-motion, and/or other coordinate frames, asdescribed herein. One or more logic devices of system 100 may be adaptedto use such parameters to transform a coordinate frame of the otherelements of system 100 to/from a coordinate frame of orientation sensor140 and/or mobile structure 101, for example. Furthermore, suchparameters may be used to determine and/or calculate one or moreadjustments to an orientation of an element of system 100 that would benecessary to physically align a coordinate frame of the element with acoordinate frame of orientation sensor 140 and/or mobile structure 101,for example, or an absolute coordinate frame and/or other desiredpositions and/or orientations. Adjustments determined from suchparameters may be used to selectively power adjustment servos/actuators(e.g., of various elements of system 100), for example, or may becommunicated to a user through user interface 120, as described herein.

FIG. 1B illustrates a diagram of system 100B in accordance with anembodiment of the disclosure. In the embodiment shown in FIG. 1B, system100B may be implemented to provide docking assist and/or otheroperational control of mobile structure 101, similar to system 100 ofFIG. 1B. For example, system 100B may include integrated userinterface/controller 120/130, secondary user interface 120, perimeterranging system 148 a and 148 b, steering sensor/actuator 150, sensorcluster 160 (e.g., orientation sensor 140, gyroscope/accelerometer 144,and/or GNSS 146), and various other sensors and/or actuators. In theembodiment illustrated by FIG. 1B, mobile structure 101 is implementedas a motorized boat including a hull 105 b, a deck 106 b, a transom107b, a mast/sensor mount 108 b, a rudder 152, an inboard motor 170,articulated thrust maneuver jet 172, an actuated sonar system 110coupled to transom 107b, perimeter ranging system 148 a (e.g., a camerasystem, radar system, and/or LIDAR system) coupled to mast/sensor mount108 b, optionally through roll, pitch, and/or yaw actuator 162, andperimeter ranging system 148 b (e.g., an ultrasonic sensor array and/orshort range radar system)) coupled to hull 105 b or deck 106 bsubstantially above a water line of mobile structure 101. In otherembodiments, hull 105 b, deck 106 b, mast/sensor mount 108 b, rudder152, inboard motor 170, and various actuated devices may correspond toattributes of a passenger aircraft or other type of vehicle, robot, ordrone, for example, such as an undercarriage, a passenger compartment,an engine/engine compartment, a trunk, a roof, a steering mechanism, aheadlight, a radar system, and/or other portions of a vehicle.

As depicted in FIG. 1B, mobile structure 101 includes actuated sonarsystem 110, which in turn includes transducer assembly 112 coupled totransom 107b of mobile structure 101 through assembly bracket/actuator116 and transom bracket/electrical conduit 114. In some embodiments,assembly bracket/actuator 116 may be implemented as a roll, pitch,and/or yaw actuator, for example, and may be adapted to adjust anorientation of transducer assembly 112 according to control signalsand/or an orientation (e.g., roll, pitch, and/or yaw) or position ofmobile structure 101 provided by user interface/controller 120/130.Similarly, actuator 162 may be adapted to adjust an orientation ofperimeter ranging system 148 according to control signals and/or anorientation or position of mobile structure 101 provided by userinterface/controller 120/130. For example, user interface/controller120/130 may be adapted to receive an orientation of transducer assembly112 and/or perimeter ranging system 148 (e.g., from sensors embeddedwithin the assembly or device), and to adjust an orientation of eitherto maintain sensing/illuminating a position and/or absolute direction inresponse to motion of mobile structure 101, using one or moreorientations and/or positions of mobile structure 101 and/or othersensor information derived by executing various methods describedherein.

In one embodiment, user interfaces 120 may be mounted to mobilestructure 101 substantially on deck 106 b and/or mast/sensor mount 108b. Such mounts may be fixed, for example, or may include gimbals andother leveling mechanisms/actuators so that a display of user interfaces120 stays substantially level with respect to a horizon and/or a “down”vector (e.g., to mimic typical user head motion/orientation). In anotherembodiment, at least one of user interfaces 120 may be located inproximity to mobile structure 101 and be mobile throughout a user level(e.g., deck 106 b) of mobile structure 101. For example, secondary userinterface 120 may be implemented with a lanyard and/or other type ofstrap and/or attachment device and be physically coupled to a user ofmobile structure 101 so as to be in proximity to mobile structure 101.In various embodiments, user interfaces 120 may be implemented with arelatively thin display that is integrated into a PCB of thecorresponding user interface in order to reduce size, weight, housingcomplexity, and/or manufacturing costs.

As shown in FIG. 1B, in some embodiments, speed sensor 142 may bemounted to a portion of mobile structure 101, such as to hull 105 b, andbe adapted to measure a relative water speed. In some embodiments, speedsensor 142 may be adapted to provide a thin profile to reduce and/oravoid water drag. In various embodiments, speed sensor 142 may bemounted to a portion of mobile structure 101 that is substantiallyoutside easy operational accessibility. Speed sensor 142 may include oneor more batteries and/or other electrical power storage devices, forexample, and may include one or more water-powered turbines to generateelectrical power. In other embodiments, speed sensor 142 may be poweredby a power source for mobile structure 101, for example, using one ormore power leads penetrating hull 105 b. In alternative embodiments,speed sensor 142 may be implemented as a wind velocity sensor, forexample, and may be mounted to mast/sensor mount 108 b to haverelatively clear access to local wind.

In the embodiment illustrated by FIG. 1B, mobile structure 101 includesdirection/longitudinal axis 102, direction/lateral axis 103, anddirection/vertical axis 104 meeting approximately at mast/sensor mount108 b (e.g., near a center of gravity of mobile structure 101). In oneembodiment, the various axes may define a coordinate frame of mobilestructure 101 and/or sensor cluster 160. Each sensor adapted to measurea direction (e.g., velocities, accelerations, headings, or other statesincluding a directional component) may be implemented with a mount,actuators, and/or servos that can be used to align a coordinate frame ofthe sensor with a coordinate frame of any element of system 100B and/ormobile structure 101. Each element of system 100B may be located atpositions different from those depicted in FIG. 1B. Each device ofsystem 100B may include one or more batteries or other electrical powerstorage devices, for example, and may include one or more solar cellmodules or other electrical power generating devices. In someembodiments, one or more of the devices may be powered by a power sourcefor mobile structure 101. As noted herein, each element of system 100Bmay be implemented with an antenna, a logic device, and/or other analogand/or digital components enabling that element to provide, receive, andprocess sensor signals and interface or communicate with one or moredevices of system 100B. Further, a logic device of that element may beadapted to perform any of the methods described herein.

FIGS. 2A-I show diagrams illustrating various aspects of a perimeterranging system for a docking assist system in accordance with anembodiment of the disclosure. For example, FIG. 2A shows diagram 200illustrating mounting positions and corresponding monitoring perimetersfor perimeter ranging system components associated with powered yachtarrangement 210 and sailboat arrangement 220.

Each type of perimeter ranging system includes a variety of its owncomplications when used to implement a docking assist system, and areliable and accurate perimeter ranging system is necessary for dockingassist because GNSS data and cartography data for docks lack sufficientdetail and resolution to provide safe docking assist by themselves andbecause, regardless of improvements in GNSS technology and cartography,there are often many uncharted navigation hazards associated withdocking. As an example, conventional radar systems can be relativelyeasy to retrofit onto a mobile structure, if mounted conventionally highup on mobile structure 101, but they typically suffer from relativelylow resolution and so can be unable to detect small objects, such asmooring lines. If mounted conventionally high, a conventional radarsystem would provide ranging data to controller 130, and controller 130would be configured to use knowledge of the profile for mobile structure101 and a measured orientation of mobile structure 101 to determineperimeter sensor data for a detected navigation hazard (e.g., theclosest approach distance between a perimeter of mobile structure 101and the detected navigation hazard). However, by being mounted high, theconventional radar system would typically miss low profile navigationhazards commonly encountered when docking a mobile structure, such asthe leading edge of a dock floating minimally above a waterline,particularly as it approaches within a meter of a perimeter of mobilestructure 101.

Conventional radar systems may instead be mounted relatively low (e.g.,pontoon height) to reliably range such low profile navigation hazards,but this would increase mounting costs and complexity and still resultin a system that could miss small but important detail either due toresolution issues or due to conventional beam shapes and correspondingdetection areas being too narrow at the point of emission and lackingsubstantial vertical coverage. Furthermore, if mounted low, aconventional radar system couldn't be used while underway at sea (e.g.,due to wave clutter), would be subject to increased risk of damageduring docking and/or due to immersion (e.g., sail boat heeled overwhile underway), would be difficult to mount aesthetically and/orrequire holes in the hull, and might require extensive cabling routing.As such, conventional radar can be a useful and relatively inexpensivecomplimentary sensor for a docking assist system, particularly whenmounted conventionally to a mast, but would typically requiresupplemental perimeter sensor data from a separate perimeter rangingsystem to provide reliable and safe docking assist.

Alternatives include ultrasonic sensor arrays, LIDAR systems, and shortrange radar systems. Conventional ultrasonic sensor arrays typically donot provide sufficient resolution and range to detect relatively smallnavigation hazards or to allow a user to specify a docking location, andso, like conventional radar systems, conventional ultrasonic sensorarrays would typically need supplemental perimeter sensor data from aseparate perimeter ranging system to provide reliable and safe dockingassist, which would increase system cost and complexity.

Newer ultrasonic sensor arrays may include relatively small individualtransducer/sensor elements each implemented with its own microcontrollerso as not to require relatively expensive shielded sensor wiring to eachelement (e.g., each element can measure and digitally communicate rangesand/or range profiles to controller 130). For example, unlike automotivesolutions which are relatively large and so have to be recessed into thebumper or other surface of the vehicle, and each requiring their ownsensor leads, single chip transducer/sensor elements are so small thatthey can be integrated into a self-adhesive strip that may be surfacemounted without significantly impacting a watercraft's aesthetics,hydrodynamic efficiency, or hull/fuselage integrity, and withoutrequiring complex wiring. Rather than having to wire each sensorindividually, an array or strip of such single chip transducer/sensorelements can be linked together (e.g., daisy chained, bus linked, meshlinked, and/or linked according to other topologies) so that the arrayincludes a single common power line input and/or a single commoncommunication line input/output, from which all chips may draw power andcommunicate with each other and/or controller 130, for example. Suchstrip or array may have a single electrical coupling at one end, so asingle cable can be routed to neatly enter into the hull through asingle hole disposed in the transom, for example, or the deck. In someembodiments, the power line may support both power delivery to theindividual sensor elements and communication between the sensor elementsand to/from controller 130. In various embodiments, such sensorarrays/strips may be integrated with and/or along a hull or gunwale of avessel.

Lidar is improving rapidly and has the advantage of being able to detectnavigation hazards without ambient light. Lidar produces a 3d pointcloud and so is suited to measuring distances to the dock, and analyticsto determine dock/obstacle vs water are straightforward since the wateris substantially a flat plane and objects more than a predeterminedthreshold above this plane can be designated as navigation hazards. TheLIDAR data can be rendered as an image from an elevated perspective,making it relatively easy and intuitive for a user to designate a targetdocking position. However, LIDAR is currently expensive, especially ifmultiple installations are required to get a clear view of the perimeterof mobile structure 101 (e.g., port and starboard installations). Shortrange radar systems (e.g., including approximate square centimeter sizedtwo and/or three dimensional radar antenna arrays configured to detectand/or range objects between a few centimeters and 10 s of meters away)are also improving rapidly, but such systems could be relatively proneto damage and would be relatively complex to mount and wire along aperimeter of mobile structure 101 in order to provide sufficientcoverage for common docking assist maneuvers.

A less expensive alternative, according to embodiments disclosed herein,is one or more cameras (e.g., including visible spectrum and/orinfrared/thermal imaging modules) mounted relatively high on mobilestructure 101 to provide a sufficient monitoring perimeter around mobilestructure 101 and a sufficient vertical perspective of a perimeter ofmobile structure 101 to reliably detect and range navigation hazardsrelatively close to the perimeter of mobile structure 101 (e.g., withina meter of the perimeter of mobile structure 101). Each camera mayinclude a microelectromechanical systems (MEMS) basedgyroscope/accelerometer sensor (e.g., similar to gyroscope/accelerometer144) configured to provide a vertical reference (e.g., corresponding tothe gravitational “down” vector) for images captured by the camera, forexample, and/or the camera and/or controller 130 may be configured todetermine a horizontal reference (e.g. corresponding to a horizon, suchas where the sea surface meets the horizon). From these references and aknown height of the camera, reliable and precise ranges between aperimeter of mobile structure 101 and a detected navigation hazard canbe determined, and without need of supplemental perimeter sensor dataand/or perimeter ranging systems, as described herein.

FIG. 2A shows diagram 200 illustrating mounting positions andcorresponding monitoring perimeters for perimeter ranging systemcomponents associated with powered yacht arrangement 210 and sailingyacht arrangement 220, in accordance with an embodiment of thedisclosure. In powered yacht arrangement 210, perimeter ranging system148 includes cameras mounted at positions 212, 214, and 216 providing amonitoring perimeter for mobile structure 101 corresponding roughly tothe combined fields of view (FOVs) 213, 215, and 217, as shown. As canbe seen from FOVs 213, 215, and 217, camera 212 may be implemented by arelatively narrow FOV navigational camera aimed substantially forwardwith respect to mobile structure 101 so as to detect navigation hazardssubstantially off the bow of mobile structure 101, both while dockingand while underway. Cameras 214 and 216 may be implemented by relativelywide FOV docking cameras (e.g., fisheye lens cameras) aimed down andover respective port and starboard sides of mobile structure 101 so asto detect navigational hazards substantially port, starboard, and/or aftof mobile structure 101. In various embodiments, one or more of cameras212, 214, and 216 may be mounted to mobile structure 101 at differentmounting points and/or using an actuated mount, so as to adjust FOVs213, 215, and 217 and/or a monitoring perimeter for perimeter rangingsystem 148 (e.g., according to a speed of mobile structure 101 and/orother operational modes for mobile structure 101 and/or system 100).

In sailing yacht arrangement 210, perimeter ranging system 148 includescameras mounted at positions 212, 214, and 216 providing a monitoringperimeter for mobile structure 101 corresponding roughly to the combinedFOVs 213, 215, and 217, as shown. As can be seen from FOVs 213, 215, and217, cameras 214 and 216 may be mounted at ends of a spreader 232 toplace them as close to the width of the beam of mobile structure 101 aspossible so they can view navigation hazards arbitrarily close to aperimeter (e.g., the hull) of mobile structure 101. Furthermore, cameras214 and 216 may be mounted such that their respective FOVs 215 and 217each at least partially overlap with FOV 213 of camera 212, so as toprovide a seamless monitoring perimeter.

More generally, perimeter ranging system 148 may include any number ofarticulated and/or non-articulated cameras mounted about mobilestructure 101 to provide a targeted monitoring perimeter (e.g., atemporally changing monitoring perimeter) and/or seamless monitoringperimeter about mobile structure 101. For example, such monitoringperimeter may increase or decrease in size with a linear and/or angularvelocity of mobile structure 101, and/or may be biased towards a linearor angular velocity of mobile structure 101 to provide a largermonitoring perimeter in the direction of motion of mobile structure 101.Controller 130 and/or perimeter ranging system 130 may be configured todetect navigation hazards within the monitoring perimeter, for example,and determine ranges to the navigation hazards and/or relativevelocities of the navigation hazards.

If the ranges to the navigation hazards are within a safety perimeterfor mobile structure 101, or the relative velocities of the navigationhazards towards mobile structure 101 are greater than a hazard velocitylimit, controller 130 may be configured to determine docking assistcontrol signals configured to cause navigation control system 190 tomaneuver mobile structure 101 to evade the navigation hazards bymaintaining or increasing the range to a navigation hazard or bydecreasing the relative velocity of the navigation hazard towards themobile structure. Such safety perimeter may be a preselected range froma perimeter of mobile structure 101 and/or from an approximate center ofmobile structure 101, for example, may be provided by a manufacturer, byregulation, and/or by user input, and may vary according to a velocityof mobile structure 101. The hazard velocity limit may be a preselectedvelocity limit corresponding to relative velocities of navigationhazards towards mobile structure 101 (e.g., the component of theirrelative velocities towards a center of mobile structure 101 and/ortowards a neared approach to a perimeter of mobile structure 101), forexample, may be provided by a manufacturer, by regulation, and/or byuser input, and may vary according to a velocity of mobile structure101.

Because cameras intrinsically measure angle to a high degree of accuracyand precision, and because the camera mounting height above the watersurface can be known accurately, it is possible to obtain reliabledistance measurements navigation hazards in view of the cameras. Forexample, FIG. 2B shows diagram 201 illustrating a range measurementassociated with perimeter ranging system 148 including docking camera216, in accordance with an embodiment of the disclosure. As shown indiagram 201, camera 216 may be mounted to mobile structure 101 at height240 above water surface 250 and in view of at least a portion of a sideof mobile structure 101 and dock 222. In various embodiments, angle 242between vertical vector 246 and navigation hazard view vector 244 may beused to find the range 248 from mobile structure 101 to dock 222, whererange 248=height 240*tan(angle 242). In various embodiments, navigationhazard view vector 244 may correspond to the position within the FOV ofcamera 216 where dock 222 intersects water surface 250, and angle 242may be determined based on operating characteristics of camera 216.

FIG. 2C shows diagram 202 illustrating a range measurement associatedwith perimeter ranging system 148 including docking camera 216, inaccordance with an embodiment of the disclosure. In particular, diagram202 shows one technique to determine angle 242 of FIG. 2B. As notedherein, water surface 250 is substantially horizontal, which can be usedto provide one of two triangle perpendiculars (e.g., the horizontalreference); the other perpendicular is a vertical reference. A verticalreference may be provided by user input indicating mounting offsets, anautomatic calibration process configured to detect vertical offsetsthrough image processing (e.g., through horizon detection or similar),and/or by gyroscope/accelerometer sensors integrated with the camera andfactory aligned to the FOV of the camera. For example, a 3 axis MEMSaccelerometer can be integrated with the camera and factory aligned toits boresight. Furthermore, the MEMS accelerometer may be combined witha MEMS gyroscope to detect and compensate for momentary accelerations ofmobile structure 101 to prevent such accelerations from introducingshort term errors in the vertical reference.

As such, in various embodiments, angle 242 can be obtained from: angle242=90−((Pixel 264−NoPixels/2)*CameraFOV 260/NoPixels)−DipAngle 266,where DipAngle 266 is the angle between horizontal reference vector 262(e.g., which is perpendicular to the vertical reference and parallel tothe horizon) and boresight vector 268, CameraFOV 260 is the verticalangular FOV of camera 216, Pixel 264 is the pixel distance between anedge of CameraFOV 260 and navigation hazard view vector 244, andNoPixels is the number of pixels across CameraFOV 260. Other techniquesare contemplated, including other techniques relying on physical and/oroperating characteristics of camera 216.

Such distance measurements require some image analytics to detect wheredock 222 intersects water surface 250. In some embodiments, controller130 may be configured to execute neural networks trained to recognizedock features and other navigation hazards such as mooring warps orother watercraft and to differentiate such navigation hazards from otherobjects such as seaweed, seagulls. Alternative and complimentarystatistical processes can be used. In some embodiments, such analyticsarchitected for minimal latency by performing the analytics beforecompressing and converting the images for further image processing. Forexample, a wired communications link may be formed between camera 216 ofperimeter ranging system 148 and controller 130 where the communicationslink enables uncompressed high speed video to be transferred down asingle cable with lower speed control and data overlaidbi-directionally.

FIG. 2D shows diagram 203 illustrating a system architecture forperimeter ranging system 148 utilizing such communication link, inaccordance with an embodiment of the disclosure. As shown in diagram203, perimeter ranging system 148 may include cameras 212, 214, and 216coupled to image analyzer 270 over wired communication links 271, whichmay be configured to provide processed imagery and analytics metadata touser interface/controller 120/130 over communication link 272. Sucharchitecture allows image analyzer 270 to provide analyticssubstantially in real time with minimal latency at relatively low cost.For example, image analyzer 270 may be implemented with a vectorprocessor (e.g., such as a Myriad 2 or Myriad 3 vector processor)coupled to a video processing integrated circuit (e.g., such as theAmbarella S3L or S5L video processing ICs). In various embodiments,image analyzer 270 may be configured to identify navigation hazards andother objects in a maritime scene, such as those shown in display viewsprovided in FIGS. 2F-I. Image analyzer 270 may be configured toprecisely stitch images received from cameras 212, 214, and 216 (e.g.,by recognizing shoreline feature and using them as a basis for aligningimages from different cameras). Also shown in diagram 203 are variousother imaging devices 180, which may include security cameras, sportscameras, smart phone cameras, and/or other imaging devices that can beconfigured to interface with image analyzer 270.

FIG. 2E shows diagram 204 illustrating a system architecture forperimeter ranging system 148 utilizing image analyzer 270, in accordancewith an embodiment of the disclosure. As shown in diagram 2E, imagingdevices 273 provide images and/or video to video processing integratedcircuit 270 a of image analyzer 270, which collaborates withco-processor 270 b of image analyzer 270 to detect and identifynavigation hazards and other objects in the images provided by imagingdevices 273. Resulting processed imagery (e.g., stitched imagery,synthetic viewpoint elevation imagery, and/or other processed imagery)and/or analytics metadata (e.g., bounding boxes, extents, type, and/orother characteristics of detected and identified navigation hazards andother objects) may then be provided to other elements of system 100,such as user interface 120 and/or controller 130.

In some embodiments, image analyzer 270 may be configured to stitchimages provided by any one or combination of cameras 212, 214, and/or216, for example, to generate an all-around view while navigating at seaand/or to generate a synthetic elevated view (e.g., a top-down view)while docking. In general, it is topologically impossible to show anall-round de-warped view by simply stitching two fisheye camera outputstogether. However, a synthetic elevated view, also referred to as avirtual drone view, may be generated from such images, which changes theviewpoint to something that can be projected onto a flat screen. Unlikeconventional automotive systems, which typically create significantdistortions with respect to nearby objects, the relatively high mountingpoint of at least cameras 214 and 216 results in less distortion andthereby facilitates producing accurate distance measurements and moreintuitive imagery. In some embodiments, such virtual drone views may bescaled so that distances can be read off directly from the display ofuser interface 120 by a user.

FIGS. 2F-J show display views 205-209 illustrating perimeter sensor datafrom perimeter ranging system 148, in accordance with an embodiment ofthe disclosure. For example, display view 205 of FIG. 2F shows an imagecaptured by camera 216 of a docking area including dock 222 afterprocessing by image analyzer 270. As shown in display view 205, dock 222has been identified (e.g., by co-processor 270 b) and highlighted with agreen overlay (e.g., provided as analytics metadata by video processingIC 270 a) to help a user guide mobile structure 101 into dock 222.Display view 206 of FIG. 2G shows an image captured by camera 212 of adocking area including dock 222 and watercraft 230 after processing byimage analyzer 270, which includes bounding boxes and identifiers (e.g.,textual names and/or ranges) associated with dock 222 and watercraft230. Display view 207 of FIG. 2H shows a thermal image captured bycamera 212 of two watercraft 230 after processing by image analyzer 270to increase contrast and/or provide identifiers for watercraft 230.Display view 208 of FIG. 2I shows a visible spectrum image captured bycamera 212 of two watercraft 230 after processing by image analyzer 270,which includes bounding boxes and identifiers associated with detectedwatercraft 230.

As noted herein, a synthetic elevated view/virtual drone view, may begenerated from images captured by cameras mounted to various portions ofmobile structure 101, such as a gunwale, bridge, mast, and/or otherportion of mobile structure 101, and a fused or stitched version of suchimages may be projected onto a flat surface and rendered in a display ofuser interface 120. For example, display view 209 of FIG. 2J shows acombination of visible spectrum images captured by cameras 212, 214, and216 coupled to mobile structure 101 and projected/mapped onto a(virtual) flat surface and rendered for display (e.g., by image analyzer270 and/or user interface 120). As shown in FIG. 2J, display view 209Ashows mobile structure 101 attempting to dock at dock 222 whilenavigating to avoid collision with other watercraft 230 and/or otherstructures identified within FOVs 213, 215, and 217. Display view 209Aalso shows various un-imaged areas 218 (e.g., where the various FOVsfail to overlap), which may in some embodiments be left blank orsupplemented with prior-image data (e.g., captured while mobilestructure 101 was at a different position or orientated differently)and/or other perimeter ranging system data, such as above or below watersonar data indicating the relative position of an object surface orunderwater hazard within un-imaged areas 218.

Another example is provided by display view 209B of FIG. 2K, which showsa combination of visible spectrum images captured by cameras 212, 214,and 216 coupled to mobile structure 101 and projected/mapped onto a(virtual) flat surface and rendered for display (e.g., by image analyzer270 and/or user interface 120), but where FOVs 213, 215, and 217corresponding to images captured by cameras 212, 214, and 216 areprocessed to generate a substantially isomorphic representation of atleast the perimeter of mobile structure 101. Such processing mayinclude, for example, linear and/or non-linear unwarping/dewarping,scaling, translating, cropping, resampling, image stitching/combining,and/or other image processing techniques configured to generate anisomorphic representation of at least the perimeter of mobile structure101 from images captured by cameras 212, 214, and 216, for instance,and/or to minimize the size and/or prevalence of un-imaged areas 218.

As shown in FIG. 2K, display view 209B shows mobile structure 101 dockedat dock 222 next to other watercraft 230 and/or other structuresidentified within FOVs 213, 215, and 217. Display view 209B also showsvarious un-imaged areas 218 (e.g., where the various processed FOVs failto overlap), which may in some embodiments be left blank or supplementedwith prior-image data and/or other perimeter ranging system data and/orother ranging system data.

To simplify installation and setup of perimeter ranging system 148, andgenerate display views 209A, 209B, and/or other display views describedherein, the various camera angles can be automaticallycalibrated/derived/determined by capturing images while maneuveringmobile structure 101 through 360° while close to dock 222, and theresulting set of images can be used to self-calibrate for camera height,distance from a centerline of mobile structure 101, and/or otheroperating and/or mounting characteristics of the cameras. For example,the calibration of the cameras may be performed automatically; when theboat executes a 360° turn in a crowded environment such as a marina orport, the images that sweep past the different cameras move out of onefield of view and into the next in a manner which is only consistentwith the yaw rate data (e.g., from orientation sensor 140) and a singleset of calibration parameters for the cameras. In alternativeembodiments, range may be measured, calibrated, and/or adjusted usingmotion of mobile structure 101 and various image analytics applied toimages captured by perimeter ranging system 148. While multiple camerascan be used in stereo to determine ranges, such arrangements undesirablyadd to system cost and complexity.

In some embodiments, cameras 212, 214, and 216 may be characterized by amanufacturer in a lab prior to use, or may be characterized by a userand a known geometry reference (e.g., a poster of images with knowngeometries placed a known distance and orientation relative to thecamera), and the resulting camera characteristics may be used todetermine unwarping parameters for an unwarping process that, forexample, removes various types of image distortions introduced by lensesand/or other physical characteristics of cameras 212, 214, and 216. Eachcamera may include an orientation sensor and/or accelerometer or similarsensor configured to provide an elevation (e.g., downward pointingangle) and/or an azimuth (e.g., relative heading/bearing) correspondingto respective FOVs 213, 215, and 217, or approximate elevations and/orazimuths may be assumed for a typical mounting (e.g., 45 degree negativeelevation and +−110 degree relative azimuth for lateral view cameras 214and 216, 10 degree negative elevation and zero degree relative azimuthfor forward view camera 212). Similarly, other installation geometriescan be estimated or assumed (e.g., all cameras mounted at an altitude of3 meters, forward view camera 212 2 meters longitudinally in front oflateral view cameras 214 and 216, lateral view cameras 214 and 216 3meters laterally apart from each other).

From these measured and/or assumed/estimated installation geometries, aninitial or estimated image stitching, unwarping, and/or other processingmay be performed to generate the isometric representation of at least aperimeter of mobile structure 101. Such initial or estimated isometricmapping may be modified and/or refined based on isometric registrationof structures imaged by spatially overlapping FOVs and/or time-spacedoverlapping FOVs (e.g., as mobile structure maneuvers and/or rotatesthrough a scene). The magnitudes of such adjustments to the isometricmapping may be adjusted over time (e.g., by a multiplicativecoefficient) and be fairly aggressive initially (e.g., coefficient closeor equal to 1) but taper off based on the number of co-registeredstructures, time of calibration, and/or other calibration parameters(e.g., coefficient trending to a value between 0.1 and zero).

Autonomous docking assist requires techniques for defining targetdocking positions and/or orientations, for example, and/or targetdocking tracks (e.g., a waypoint defined path from a current positionand orientation of mobile structure 101 to a target docking positionand/or orientation, which may include a series of waypoints indicatingcorresponding series of positions and/or orientations for mobilestructure 101). Such target docking tracks may include one or morespecified target linear and/or angular velocities along the track,target transit times, target mobile structure orientations, and/or otherdocking track characteristics, for example, which may be selected by auser and/or specified by various docking safety parameters (e.g.,regulations or user-supplied limits on maneuvers within a docking area).Thus, a docking assist user interface should include display viewsallowing a user to specify target docking positions and/or orientations,and/or target docking tracks, as described herein.

In some embodiments, user interface 120 and/or controller 130 may beconfigured to render, on a display of user interface 120, a selectableimage or icon representing at least the profile of mobile structure 101over a navigational chart of a docking area and/or a camera image of anarea surrounding mobile structure 101 and including the docking area,captured by perimeter ranging system 148. Such icon may be moved acrossthe chart or image by user input (e.g., user touch, joystick input,mouse input, and/or other user input) to indicate a target docking trackand/or a target docking position and/or orientation within the generatedview of the docking area. Typically, a user would manually steer mobilestructure 101 to a point in clear view of a target berth, then stopmobile structure 101, and then engage an autonomous docking mode. Thedocking assist system may be configured to hold the position and/ororientation of mobile structure 101 while the user defines the targetdocking track and/or a target docking position and/or orientation, whichmay in some embodiments be performed using a two finger slide/rotate ofthe icon/image corresponding to mobile structure 101 through the dockingarea as presented by the chart and/or image of the docking area. In someembodiments, such movement of the icon/image within the rendered viewrelative to various navigation hazards may be limited by a predefinedminimum safety perimeter, as disclosed herein, which may be set toapproximately 20 cm.

Advantageously, embodiments provide a user substantial influence overdocking maneuvers; for example, the user may choose when to engage theautonomous docking process (e.g., the user may define both a startingpoint and an ending point of the docking maneuver). A user wishing toexercise relatively tight control over the starting point can engage theautonomous docking process closer to the target docking position,whereas a user wishing less control over the process could engageearlier, thereby allowing the docking assist system to manage more ofthe maneuver. In some embodiments, a safety limit may limit how earlythe process can be engaged, such as no further than 20 boat lengths fromthe target docking position.

Docking assist system 100 may also be configured to provide varioustypes of convenience-centric target selection techniques when renderinga docking assist user interface, as described herein. For example, adocking assist user interface may include a selection of favorite orpre-memorized ‘home’ or commonly used target docking positions andorientations. A docking assist user interface may also include a listingof auto-prompted best docking positions corresponding to a selecteddocking area, a current position of mobile structure 101, a currenttraffic within the selected docking area, and/or other docking areacharacteristics and/or operational status of mobile structure 101.

In some embodiments, docking assist system 100 may be configured todetect an optical target positioned and/or held at a target dock and/orslip/berth (e.g., using perimeter ranging system 148) and determine thetarget docking position and/or orientation based on the position and/ororientation of the optical target. Similarly, docking assist system 100may be configured to detect a system of fixed optical targets (e.g.,provided by a marina) and identify a target docking position,orientation, and/or track indicated by the system of fixed opticaltargets. In a further embodiment, docking assist system 100 may beconfigured to identify a target docking position and/or orientationbased on a berth reference (e.g., provided by user input) associatedwith a charted and/or imaged docking area.

In addition to receiving selection of target docking position,orientation, and/or track, docking assist system 100 may be configuredto adjust and/or reroute a selected target docking position,orientation, and/or track according to navigation hazards detected alongthe docking track by perimeter ranging system 148 and/or any externaldisturbances (e.g., wind and/or water currents affecting navigation ofmobile structure 101). For example, docking assist system 100 may beconfigured to maintain a safety perimeter to navigation hazards and/orother objects, which may be speed dependent. In some embodiments,prevailing wind and water currents may be stronger than the maximumthrust of thrust maneuver system 172, for example, or thrust maneuversystem 172 may be absent, and docking assist system 100 may beconfigured to maintain a relatively high velocity using propulsionsystem 170 until relatively close to a target docking position, then usea combination of reverse thrust provided by propulsion system 170,steering input provided by steering actuator 150, and/or supplementalvectored thrust provided by optional thrust maneuver system 172 to slowand/or orient mobile structure 101 just before entering the targetdocking position and/or orientation.

In various embodiments, docking assist system 100 may be configured tocompensate for slip dynamics of mobile structure 101 (e.g., unlike roadvehicles that follow a prescribed direction of travel, watercraft slipsideways when they turn and this leeway effect can be significant at lowspeeds and very significant for power boats which have almost no keel)and/or for other operating characteristics of mobile structure 101, suchas the effects of prop torque, which tends to turn a watercraft.

In addition, a target track for a powered watercraft will typically bedifferent from the target track for a sailing watercraft: a sailboat canaim at the docking pontoon and turn at the last second because its keelsubstantially prevents sideslip; a powerboat should turn a few secondsearlier because its sideslip is typically significant and can cause thepowerboat to drift sideways at the docking pontoon and potentially causedamage to its hull; a zodiac should tend to aim 45° to the side of adocking pontoon, coasting in during the last 5 or so seconds, andapplying a burst of full reverse helm in the last 2 or so seconds, toslow the zodiac and tuck its stern into the docking berth.

The simplest target docking tracks are for mobile structures with thrustmaneuver systems providing full control of sideways and rotationalthrust. However, in the general case, a docking track generation processis non-linear and cannot be solved simply. As such, embodimentsdisclosed herein may be configured to execute a control loop including anon-linear dynamic model of mobile structure 101, including navigationcontrol system 190, sideslip characteristics, and wind and water currentdisturbances, and computing such model iteratively with respect to astarting state of mobile structure 101, a target docking position andorientation, and known navigation hazards. Such model provides targetlinear and angular velocities along the target docking track and cananticipate slide-slip. Embodiments disclosed herein may also designate atarget docking track according to a set of predefined docking trackpatterns which are linked mobile structure type. Such patterns may beadjusted to fit a particular docking area and/or circumstance. Suchdocking track patterns may in some embodiments be learned from a userproviding user input during a manual docking process, such as part of atraining process; this can be done in real time or offline from a largedatabase of recorded docking maneuvers. More specifically with regard toa docking assist user interface, docking assist system 100 may beconfigured to receive a target docking track as user input provided touser interface 120 as the user drags the icon/image of mobile structure101 across a rendered chart or image of a docking area to a targetdocking position.

FIGS. 3A-E show display views and selected target docking tracks for adocking assist system in accordance with an embodiment of thedisclosure. For example, display view 300 of FIG. 3A shows a chart 320of a docking area proximate mobile structure 101 and including multipledocks 322, slips or berths 324, docking area channels 326, sea wall 328,and other watercraft 330. In some embodiments, a user may select icon101 (corresponding to a position of mobile structure 101) and drag italong channel 326 to a target docking position 324. In display view 300,a pop up menu may be provided to select a target docking orientation formobile structure 101, since icon 101 only indicates position. In otherembodiments, a user may select a berth or slip ID and docking assistsystem 100 may be configured to determine a target docking track to thecorresponding berth or slip 324. Docking assist system 100 may beconfigured to adjust the determined target docking track according tovarious docking safety parameters and/or charted navigation hazards, forexample, and may be configured to evade uncharted navigation hazardswhile maneuvering along the determined target docking track, asdescribed herein.

Display view 301 of FIG. 3B shows an image 321 of a docking areaproximate mobile structure 101 and including docks 322, slip 324, andmooring lines 325. Also shown in display view 301 is a user providinguser selection 340 to drag mobile structure icon 101 from startingposition and/or orientation “1” along target docking track 342 and totarget docking position and/or orientation “2”. In some embodiments, auser may employ a two finger touch to a touchscreen display of userinterface 120 to identify target docking track 342 and/or target dockingposition and/or orientation “2”. A user may employ similar techniques todesignate the target docking track (“1” through “4” and/or targetdocking position and/or orientation “4” in display view 302 of FIG. 3C.Display view 302 illustrates it can be nonobvious how a user wishes todock mobile structure 101, and in the illustrated example, the user haschosen to be stern too, rather than side or bow too. Even when side too,a user may choose port or starboard sides as preferred due to winddirection, proximity to friends next door, facility to refuel, etc. Alsoshown in display view 302 are posts 325, which may be used to moormobile structure 101.

Display view 303 of FIG. 3D shows an image or chart of a docking areaproximate mobile structure 101 and including dock 322, target dockingpath 342, and water current disturbance indicator 360. As shown, dockingassist system 100 has determined target docking path 342 so as tocompensate for water current disturbance 360 and simplify docking ofmobile structure 101 to dock 322. Display view 304 of FIG. 3E shows andimage or chart of a docking area proximate mobile structure 101 andincluding dock 322, slip 324, other docked watercraft 330, initialportion of target docking path 342 a, final portion of target dockingpath 342 b, and wind disturbance indicator 362. As shown, docking assistsystem 100 has determined target docking paths 342 a and 342 b so as tocompensate for wind disturbance 362 and dock mobile structure 101 atslip 324 of dock 322.

A particular selected target docking operation (e.g., a target dockingposition, orientation, and/or track) may or may not be achievable giventhe available maneuvering capability of mobile structure 101 and/or adistribution of navigation hazards and/or corresponding docking safetyparameters. Docking assist system 100 may be configured to evaluate aselected target docking operation and allow or confirm or engage suchselection only if the operation is achievable. To evaluate a selectedtarget docking operation, docking assist system 100 may be configured tosimulate the target docking process using a dynamic model of the dockingprocess, including maneuvering characteristics of mobile structure 101and any navigation hazards and/or external disturbances, as describedherein. Such dynamic model (e.g., described more fully with respect toFIGS. 4-11 and 13-24) may be used to simulate and thereby evaluate aselected target docking track, for example, and to automaticallydetermine a target docking track (e.g., based, at least in part, on aselected target docking position and/or orientation). Moreover, suchdynamic model may be used to evade a navigation hazard and/or tocompensate for changing external disturbances.

For assisted docking, as opposed to fully autonomous docking, a user mayprovide primary control of maneuvering of mobile structure 101 throughuser interface 120 (e.g., a helm or joystick, for example), and dockingassist system 100 may be configured to adjust and/or modify such userinput to facilitate docking of mobile structure 101, such as byproviding for intuitive control of maneuvering of mobile structure 101and/or by overriding or modifying user input that would otherwise riskdamage caused by impact with navigation hazards.

For example, docking assist system 100 may be configured to convert astandard joystick thrust controller (e.g., providing forward, backward,sideways, and/or rotational thrust in response to user inputmanipulating the joystick) into a joystick velocity controller (e.g.,providing a linear and/or angular velocity in response to user inputmanipulating the joystick). Such conversion results in a controller thatis analogous to cruise control in a road vehicle where the throttlepedal is switched out for a speed demand. Such conversion may be basedon known characteristics of mobile structure 101 and navigation system190, for example, or may be based on system characteristics derived froma calibration process, such as a sea trial, where the control signalsare provided to navigation control system 190 and the resulting motionof mobile structure 101 and other effects are measured (e.g., usingsensors 140-148), creating calibration parameters linking control signalinput and motive reaction.

A sideslip factor for mobile structure 101 may also be determined basedon such sea trial calibrations, or may be provided by a manufacturer.Such calibration processes would typically be performed while perimeterranging system 148 is active and able to operate sufficiently well toestimate velocity based on perimeter sensor data corresponding to nearbynavigation hazards, for example, but where mobile structure 101 is notat risk of collision with navigation hazards. Wind and/or watercurrents, and/or other external disturbances, may be estimated usingsuch systems, such as by placing docking assist system 100 in a hovermode (e.g., by providing user input corresponding to a dead stick inputto user interface 120), where the target linear and/or angularvelocities are substantially zero, such as prior to engaging autonomousdocking, as described herein. Any thrust necessary to keep mobilestructure 101 from moving may be attributed to an appropriate externaldisturbance (e.g., as modulated by other sensors, such as speed sensor142).

In related embodiments, docking assist system 100 may be configured toprovide “brakes” for mobile structure 101 corresponding to such hovermode, where the system uses navigation control system 190 to keep mobilestructure substantially still, even while buffeted by various externaldisturbances. Docking can be frightening, especially so when wind orwater currents are strong. Aside from anchors, which are severelylimited in application when attempting to maneuver into a docking area,there are no true brakes for watercraft, and so it often requirescontinual skillful thrust control to hover a watercraft usingconventional navigation controllers. By converting the thrust controllerinto a velocity controller, as described herein, embodiments allow auser to hover or halt mobile structure 101 simply by letting go of thejoystick. In some embodiments, controller 130 may be configured to limita linear and/or angular velocity generated by docking assist system 100to a value that can be sufficiently counteracted to hover mobilestructure 101 within a predefined period of time (e.g., 2-3 seconds)and/or a predefined linear and/or angular motion of mobile structure 101(e.g., 0.5 meters and/or 1 degree of rotation). Such control is moreintuitive, particularly for novice users, and provides an additionalsafety measure when utilizing docking assist, where fine navigationcontrol can be critical.

In additional embodiments, docking assist system 100 may be configuredto provide collision avoidance while substantially adhering to theprovided user input. For example, embodiments of the present disclosureprovide full control over the path mobile structure 101 takes andprovide the ability to stop at any time. In addition, by monitoring aperimeter about mobile structure 101, embodiments are able to modifyand/or override user input to prevent a collision, such as if a useroverlooks a detected navigation hazard, tries to approach a dock at toohigh a speed, or otherwise makes a navigation mistake.

FIGS. 4-11 illustrate flow diagrams of control loops to provide dockingassist (e.g., assisted and/or fully automated docking) in accordancewith embodiments of the disclosure. In some embodiments, the operationsof FIGS. 4-11 may be performed by controller 130 processing and/oroperating on signals received from one or more of sensors 140-148,navigation control system 190, user interface 120, and/or other modules180. For example, in various embodiments, control loop 400 (and/or othercontrol loops of FIGS. 5-11) may be implemented and/or operatedaccording to any one or combination of the systems and methods describedin International Patent Application No. PCT/US2014/13441 filed Jan. 28,2014 and entitled “STABILIZED DIRECTIONAL CONTROL SYSTEMS AND METHODS,”and/or U.S. patent application Ser. No. 14/321,646 filed Jul. 1, 2014and entitled “STABILIZED DIRECTIONAL CONTROL SYSTEMS AND METHODS,” eachof which are hereby incorporated by reference in their entirety.

In accordance with an embodiment, each block may be implemented entirelyas instructions executed by controller 130, for example, or may beimplemented in a combination of executable instructions and hardware,such as one or more inductors, capacitors, resistors, digital signalprocessors, and other analog and/or digital electronic devices. Itshould be appreciated that any step, sub-step, sub-process, or block ofin the control loops may be performed in an order or arrangementdifferent from the embodiment illustrated by FIGS. 4-11. For example,although control loop 400 includes block 440, in other embodiments,block 440 may not be present, for example, and/or may be replaced withone or more sensors providing corresponding measured data.

As shown in FIG. 4, control loop 400 includes target maneuver block 410providing a target linear and/or angular velocity for mobile structure101 to velocity controller block 420. Target maneuver block 410 may beconfigured to receive a time series of user input from user interface120, for example, and convert it into a corresponding time series oftarget linear and/or angular velocities. For example, target maneuverblock 410 may be configured to effectively convert a thrust controllerinto a velocity controller, as described herein. Such conversion may bebased, at least in part, on a maximum linear and/or angular thrust fornavigation control system 190 and/or thrust maneuver system 172, forexample, such that the maximum linear and/or angular velocity output bytarget maneuver block 410 is limited by the time or distance it wouldrequire to hover mobile structure 101 given maximum counteracting linearand/or angular thrust, as described herein. In other embodiments, targetmaneuver block 410 may be configured to receive a time series of targetlinear and/or angular velocities corresponding to a target docking trackand/or a target docking position and/or orientation, as describedherein, which may be adjusted to evade one or more navigation hazards,and forward them on to velocity controller block 420.

Velocity controller block 420 receives the target linear and/or angularvelocity from target maneuver block 410 and a current measured linearand/or angular velocity of mobile structure 101 from measurement block470 and generates a thrust demand (e.g., a linear and/or angular thrustdemand) based on the received target and current linear and/or angularvelocities and provides it to thrust controller block 430. When controlloop 400 is used to model maneuvering of mobile structure 101, thrustcontroller 430 simply converts the thrust demand into a correspondingthrust force (e.g., a linear and/or angular thrust force) and providesthe thrust force to vessel dynamics block 460. When control loop 400 isused to control maneuvering of mobile structure 101, thrust controller430 may be configured to provide docking assist control signalscorresponding to the thrust demand received from velocity controller 420to navigation control system 190 (e.g., to one or more of steeringsensor/actuator 150, propulsion system 170, and/or thrust maneuversystem 172) in order to control maneuvering of mobile structure 101.

When control loop 400 is used to model maneuvering of mobile structure101, vessel dynamics block 460 aggregates the thrust force provided bythrust controller 430, external disturbance velocities provided bydisturbances block 440, and/or model errors provided by model errorblock 450 and converts them into expected linear and angular velocitiesfor mobile structure 101, which are then provided to measurement block470. While control loop 400 is used to model maneuvering of mobilestructure 101, measurement block 470 may be configured to receive theexpected linear and angular velocities for mobile structure 101 fromvessel dynamics block 460 and generate simulated measurements of theexpected linear and angular velocities for mobile structure 101 (e.g.,by adding in a measurement delay, for example), which are then providedto velocity controller 420 to update the model.

When control loop 400 is used to control maneuvering of mobile structure101, measurement block 470 may be configured to receive measured linearand angular velocities for mobile structure 101 (e.g., from sensors140-148) and provide them to velocity controller 420 to proceed throughanother iteration of control loop 400. In some embodiments, measurementblock 470 may be configured to receive or request such measurements uponreceiving expected linear and angular velocities for mobile structure101 from vessel dynamics block 460, so as to provide timing linking forcontrol loop 400, for example. Other timing linking for control loop 400may be accomplished by receiving or requesting such measurements uponnavigation control system 190 receiving docking assist control signalsfrom thrust controller 430. In alternative embodiments, measurementblock 470 may be configured to operate asynchronously with respect toone or more other blocks of control loop 400.

As shown in FIG. 5, in some embodiments, target maneuver block 410 mayinclude input blocks 510 configured to receive a time series of userinput from user interface 120 and convert the time series of user inputinto target linear and angular velocities for mobile structure 101, forexample, or to receive a time series of target linear and/or angularvelocities corresponding to a target docking track and/or dockingposition and/or orientation, and forward the time series of targetlinear and angular velocities as output of target maneuver block 410.

As shown in FIG. 6, in some embodiments, velocity controller 420 mayinclude breakout block 422, thrust demand blocks 424, and thrust demandconditioner blocks 426. As shown in FIG. 7, breakout block 422 may beconfigured to receive target and current linear and angular velocitiesfor mobile structure 101 and split them into components to be providedto thrust demand blocks 424. As shown in FIG. 8, (e.g., showing onlylateral velocities, though similar to longitudinal and rotational (yaw)velocities) each thrust demand block 424 may be configured to generate alinear or angular thrust demand based on corresponding target andcurrent linear or angular velocities for mobile structure 101. In FIG.8, the current velocity is converted into a predicted thrust force byblock 814 (e.g., based on an inverted dynamic model for a nominalvehicle corresponding to mobile structure 101). The target velocity isconverted into a nominal thrust demand by block 810, combined with thepredicted thrust force at block 820, and the resulting raw disturbanceis fed back into the nominal thrust demand at block 812 to produce thethrust demand as output. Blocks 818 and 822 clamp and filter thefeedback loop, respectively, so that the output thrust demand is withinbounds and to reduce a noise level of the raw disturbance, and therein,the output thrust demand. Thrust demand conditioner blocks 426 furthercondition the thrust demand before providing it as output by limitingminor numerical oscillations and large signal changes (e.g., which couldotherwise overwork the navigation controller and/or cause it to fail).

As shown in FIG. 9A, in some embodiments, disturbances block 440 mayinclude disturbance inputs 910 receiving measurements corresponding towind velocities and water current velocities (e.g., magnitude anddirection) and be configured to provide the disturbances as a singleoutput to vessel dynamics block 460. In other embodiments, disturbancesblock 440 may be configured to receive other collateral sensor data,such as GNSS data and/or wind or water speed data, for example, and todetermine the wind and water current velocities based on the collateralsensor data, as described herein.

As shown in FIG. 9B, in some embodiments, model error block 450 mayinclude model inputs 920 receiving mobile structure characteristics(e.g., mass, moment of inertia, and any motion damping coefficients,such as direction/rotation-specific and/or medium-specific dampingcoefficients) corresponding to mobile structure 101 and be configured toprovide the mobile structure characteristics as a single output tovessel dynamics block 460. In other embodiments, model error block 450may be configured to receive other collateral sensor data, such as GNSSdata and/or wind or water speed data, for example, and to estimate themobile structure characteristics based on the collateral sensor data, asdescribed herein.

As shown in FIG. 10, in some embodiments, vessel dynamics block 460 mayinclude disturbance model block 1010, which may be configured to receivedisturbance velocities and an estimated heading for mobile structure 101and provide a wind force (e.g., dependent on an orientation of mobilestructure 101 relative to the wind direction) and a water currentvelocity. In some embodiments, disturbance model block 1010 may beimplemented similarly to disturbance model block 1710 illustrated indetail in FIG. 18. The wind force is combined with the thrust force(e.g., provided by thrust controller 430 in FIG. 4) and provided tocombinatorial blocks 1012.

Combinatorial blocks 1012 convert the model errors corresponding tolinear and rotational inertia into mass and inertia errors and dividethe already combined wind and thrust forces by the mass and inertiaerrors to produce a model and disturbance corrected thrust acceleration.The corrected thrust acceleration is integrated by block 1014 to providean expected linear and angular velocity for mobile structure 101, whichis then output by block 460. The water current velocity is combined withthe expected linear and angular velocity for mobile structure 101provided by block 1014 and the resulting relative water velocity isprovided to motion damping block 1016. Motion damping block 1016determines the drag acceleration (e.g., related to drag force) on mobilestructure 101 caused by its relative motion within a body of water andprovides it to block 1017. Block 1017 applies a drag error to the dragacceleration to generate a corrected drag acceleration, which iscombined with the corrected thrust acceleration provided bycombinatorial blocks 1012, as part of a feedback loop, at block 1013.

In some embodiments, vessel dynamics block 460 may also includereference frame conversion block 1018 configured to convert the expectedlinear velocity of mobile structure 101 provided by block 1014 (e.g.,which may be in a lateral/longitudinal local reference frame for mobilestructure 101) into an expected linear velocity as represented in anabsolute reference frame (e.g., east and north), which may be combinedwith the expected angular velocity of mobile structure 101 provided byblock 1014 and provided to integrator block 1020 to provide a heading ofmobile structure 101 (e.g., which may be fed back to blocks 1010 and1018, as shown). In some embodiments, reference frame conversion block1018 may be implemented similarly to reference frame conversion block1718 illustrated in detail in FIG. 19.

As shown in FIG. 11, in embodiments where control loop 400 is used tomodel maneuvering of mobile structure 101, measurement block 470 mayinclude linear velocity transfer function blocks 1110 and rotationalvelocity transfer function block 1112 each configured to model ameasurement delay and provide such measurement delayed linear androtational velocities as output, which are then provided to velocitycontroller 420 to update the model. In some embodiments, the transferfunction blocks may be implemented as first order filters. Inembodiments where control loop 400 is used to control maneuvering ofmobile structure 101, measurement block 470 may instead include blocksconfigured to receive measured linear and angular velocities for mobilestructure 101 (e.g., from sensors 140-148), which may be provided asoutput to velocity controller 420 to proceed through another iterationof control loop 400. In various embodiments, measurement block 470 mayinclude blocks configured to receive measured linear and angularvelocities for mobile structure 101 for mobile structure 101 fromperimeter ranging system 148.

FIG. 12 illustrates plots of various control signals generated bydocking assist system 100, in accordance with embodiments of thedisclosure. For example, plots 1210 show target velocities plotted withmeasured velocities (e.g., lateral velocities along row 1220,longitudinal velocities along row 1222, and angular velocities along row1224) and plots 1212 show corresponding thrust demands (e.g., lateralthrust demands along row 1220, longitudinal thrust demands along row1222, and angular thrust demands along row 1224). In the embodimentshown in FIG. 12, at time 5 s, external disturbances are imposed(significant wind and water currents suddenly hit), and the thrustdemand can be seen to react, correcting the velocity buildup, andinitially hovering mobile structure 101. As mobile structure 101 ismoved according to the target velocities, the linear thrusts change,adapting to the “rotating” disturbance vector.

FIGS. 13-21 illustrate flow diagrams of control loops to provide dockingassist (e.g., assisted and/or fully automated docking) in accordancewith embodiments of the disclosure. In particular, by contrast tocontrol loop 400 of FIG. 4, FIGS. 13-21 illustrate control loopsconfigured to accept user input corresponding to a series of positionsand/or headings for mobile structure 101, such as those implementing atarget docking track, as described herein.

In some embodiments, the operations of FIGS. 13-21 may be performed bycontroller 130 processing and/or operating on signals received from oneor more of sensors 140-148, navigation control system 190, userinterface 120, and/or other modules 180. For example, in variousembodiments, control loop 1300 (and/or other control loops of FIGS.14-21) may be implemented and/or operated according to any one orcombination of the systems and methods described in International PatentApplication No. PCT/US2014/13441 filed Jan. 28, 2014 and entitled“STABILIZED DIRECTIONAL CONTROL SYSTEMS AND METHODS,” and/or U.S. patentapplication Ser. No. 14/321,646 filed Jul. 1, 2014 and entitled“STABILIZED DIRECTIONAL CONTROL SYSTEMS AND METHODS,” each of which arehereby incorporated by reference in their entirety.

In accordance with an embodiment, each block may be implemented entirelyas instructions executed by controller 130, for example, or may beimplemented in a combination of executable instructions and hardware,such as one or more inductors, capacitors, resistors, digital signalprocessors, and other analog and/or digital electronic devices. Itshould be appreciated that any step, sub-step, sub-process, or block ofin the control loops may be performed in an order or arrangementdifferent from the embodiment illustrated by FIGS. 13-21. For example,although control loop 400 includes block 440, in other embodiments,block 450 may not be present, for example.

As shown in FIG. 13, control loop 1300 includes target maneuver block1310 providing a target maneuver to position controller block 1320. Insome embodiments, the target maneuver may include a target docking trackand/or a corresponding target docking track speed (e.g., the desiredand/or maximum speed along a target docking path from a current positionof mobile structure 101 to a target docking position and/ororientation). In other embodiments, the target maneuver many include atarget docking position and/or orientation, a target docking heading(e.g., the desired general heading from which to initiate a targetdocking track), and/or a corresponding target docking track speed. Asdescribed herein, a target docking track may include (e.g., as an endpoint) a target docking position and/or orientation.

In some embodiments, target maneuver block 1310 may be configured toreceive user input from user interface 120, for example, and generate atarget docking track, target docking position and/or orientation, atarget docking heading, and/or target docking track speed correspondingto the received user input. In other embodiments, any such targetmaneuver may be provided by a memory device, an autopilot, and/or otherelement of system 100 of FIG. 1A and/or process executed by one or moreelements of system 100 of FIG. 1A. Target maneuver block 1310 may alsobe configured to receive a series of such target maneuvers, as describedherein, which may be adjusted and/or include adjustments to evade one ormore navigation hazards, for example, and forward them on to positioncontroller block 1320.

Position controller block 1320 receives the target maneuver from targetmaneuver block 1310 and a current measured position, orientation, and/orvelocity of mobile structure 101 from measurement block 1370 andgenerates a controller demand (e.g., a user interface or joystickdemand) based on the received target maneuver and current measured stateof mobile structure 101 and provides it to thrust controller block 1330.When control loop 1300 is used to model maneuvering of mobile structure101, thrust controller 1330 simply converts the controller demand into acorresponding thrust force (e.g., a linear and/or angular thrust force)and provides the thrust force to vessel dynamics block 1360. Whencontrol loop 1300 is used to control maneuvering of mobile structure101, thrust controller 1330 may be configured to provide docking assistcontrol signals corresponding to the controller demand received fromposition controller 1320 to navigation control system 190 (e.g., to oneor more of steering sensor/actuator 150, propulsion system 170, and/orthrust maneuver system 172) in order to control maneuvering of mobilestructure 101. In alternative embodiments, position controller block1320 and thrust controller 1330 may be modified to provide/receive athrust demand and generate a corresponding thrust force and provide thethrust force to vessel dynamics block 1360, similar to blocks 420 and430 of control loop 400 of FIG. 4.

When control loop 1300 is used to model maneuvering of mobile structure101, vessel dynamics block 1360 aggregates the thrust force provided bythrust controller 1330, external disturbance velocities provided bydisturbances block 440, and/or model errors (e.g., provided by anoptional model error block 450, as shown in FIG. 4) and converts theminto expected positions, orientations, and velocities (e.g., expectedmaneuvers) for mobile structure 101, which are then provided tomeasurement block 1370, as shown. While control loop 1300 is used tomodel maneuvering of mobile structure 101, measurement block 1370 may beconfigured to receive the expected maneuvers for mobile structure 101from vessel dynamics block 1360 and generate simulated measurements ofthe expected maneuvers for mobile structure 101 (e.g., by adding in ameasurement delay, for example), which are then provided to positioncontroller 1320 to update the model.

When control loop 1300 is instead used to control maneuvering of mobilestructure 101, measurement block 1370 may be configured to receivemeasured positions, orientations, and velocities for mobile structure101 (e.g., from sensors 140-148) and provide them to position controller1320 to proceed through another iteration of control loop 1300. In someembodiments, measurement block 1370 may be configured to receive orrequest such measurements upon receiving expected linear and angularvelocities for mobile structure 101 from vessel dynamics block 1360, soas to provide timing linking for control loop 1300, for example. Othertiming linking for control loop 1300 may be accomplished by receiving orrequesting such measurements upon navigation control system 190receiving docking assist control signals from thrust controller 1330. Inalternative embodiments, measurement block 1370 may be configured tooperate asynchronously with respect to one or more other blocks ofcontrol loop 1300.

In general, the origin from which to model or implement various aspectsof a target maneuver may be set to be any point, such as a targetdocking position, for example. By setting the origin to such endposition of a target maneuver, renderings of maneuvering of mobilestructure 101 according to the target maneuver (e.g., shown on a displayof user interface 120) would adjust more naturally as the maneuverevolved; small changes in image geometry as a camera position shiftsthrough a docking maneuver, in images provided by perimeter rangingsystem 148, would allow the destination origin to naturally adjust.However, for modeling purposes, it can be easy to initialize the modelby setting the origin to the current or starting position, orientation,and/or velocity of mobile structure 101. In various embodiments, theterm “speed” may refer to the longitudinal component of the velocity ofmobile structure 101 and/or the component of its velocity along acorresponding target maneuver (e.g., a target docking track), or a trackspeed. This definition makes a target maneuver a ‘human’ definition;humans naturally think about the path a mobile structure will take, howfast it will go, and which way it will point. Humans often do not planexactly how long a maneuver will take or at what time a mobile structureshould be at a certain position. Such definition allows a maneuver to bedefined with low granularity; as few as 4 or 5 waypoints are enough todefine it. In some embodiments, system 100 may be configured to generatea target docking track (e.g., from user input designating a series ofwaypoint) with rounded corners, such as corners with 30 degree chamfers,for example, or adjustable chamfers, such as between approximately 10degree to 45 degree chamfers.

In general, target maneuver block 1310 may be implemented similarly totarget maneuver block 410 of FIG. 5 and include input blocks similar toinput blocks 510 of FIG. 5 configured to receive user input from userinterface 120 and convert the user input into target maneuvers formobile structure 101, for example, or to receive a series of targetmaneuvers corresponding to a target docking track, and forward theseries of target maneuvers as output of target maneuver block 1310.

As shown in FIG. 14, in some embodiments, position controller 1320 mayinclude error block 1410, controller demand blocks 1420, and controllerdemand conditioner blocks 1426. As shown in FIGS. 14 and 22, error block1410 may be configured to receive target maneuvers and a current statefor mobile structure 101 and generate corresponding target maneuvererrors, which are then provided to controller demand blocks 1420. Asshown in FIG. 15, (e.g., showing only lateral demands, though similar tolongitudinal and rotational (yaw) demands) each controller demand block1320 may be configured to generate a linear or angular controller demandbased on corresponding target maneuver errors for mobile structure 101.

In FIG. 15, the current velocity is converted into a predictedcontroller demand by block 1514 (e.g., based on an inverted dynamicmodel for a nominal vehicle corresponding to mobile structure 101) andclamped by block 1516. The target maneuver error is converted into anominal controller demand by block 1510, combined with the predictedcontroller demand at block 1520, and the resulting raw disturbance isfed back into the nominal controller demand at block 1512 to produce thecontroller demand as output. Blocks 1518 and 1522 clamp and filter thefeedback loop, respectively, so that the output controller demand iswithin bounds and to reduce a noise level of the raw disturbance, andtherein, the output controller demand. Controller demand conditionerblocks 1426 of FIG. 14 further condition the controller demand beforeproviding it as output by limiting minor numerical oscillations andlarge signal changes (e.g., which could otherwise overwork thenavigation controller and/or cause it to fail). In alternativeembodiments, controller demand blocks 1420, as shown in FIGS. 14-15, maybe modified to provide a thrust demand as output, similar to blocks 424of velocity controller 420 of control loop 400 as shown in FIGS. 4, 6,and 8.

As noted herein, when control loop 1300 is used to control maneuveringof mobile structure 101, thrust controller 1330 may be configured toprovide docking assist control signals corresponding to the controllerdemand received from position controller 1320 to navigation controlsystem 190 in order to control maneuvering of mobile structure 101. Whencontrol loop 1300 is instead used to model maneuvering of mobilestructure 101, thrust controller 1330 may include conversion block 1610,as shown in FIG. 16, which may be configured to convert controllerdemands received from position controller 1320 into corresponding thrustforces (e.g., a linear and/or angular thrust forces) and provide thethrust forces to vessel dynamics block 1360. In alternative embodiments,conversion block 1610 and thrust controller 1330 may be modified toreceive a thrust demand and generate a corresponding thrust force andprovide the thrust force to vessel dynamics block 1360, similar to block430 of control loop 400 of FIG. 4.

As shown in FIG. 17, in some embodiments, vessel dynamics block 1360 mayinclude disturbance model block 1710, which may be configured to receivedisturbance velocities and an estimated heading for mobile structure 101and provide a wind force (e.g., dependent on an orientation of mobilestructure 101 relative to the wind direction) and a water currentvelocity. The wind force is combined with the thrust force (e.g.,provided by thrust controller 1330 in FIG. 16) and provided tocombinatorial blocks 1712. As shown in FIG. 18, in some embodiments,disturbance model block 1710 may include coordinate system conversionblocks 1810 and 1812, which may be configured to convert typicalcoordinates for wind and current directions (e.g., polar coordinates)into Cartesian coordinates for further processing and/or output bydisturbance model block 1710. Disturbance model block 1710 may alsoinclude wind force blocks 1820 configured to convert a wind disturbancevelocity (e.g., which may be a relative wind disturbance velocity) andconvert it into a wind force acting on mobile structure 101, for outputby disturbance model block 1710, as shown.

Combinatorial blocks 1712 of disturbance model block 1710 convert modelerrors (e.g., shown in FIG. 17 as no error, or a multiplicative errorcoefficient of 1) corresponding to linear and rotational inertia intomass and inertia errors and divide the already combined wind and thrustforces by the mass and inertia errors to produce a model and disturbancecorrected thrust acceleration. The corrected thrust acceleration isintegrated by block 1714 to provide an expected linear and angularvelocity for mobile structure 101. The linear velocity is output byblock 1360. The water current velocity is combined with the expectedlinear and angular velocity for mobile structure 101 provided by block1714 and the resulting relative water velocity is provided to motiondamping block 1716. Motion damping block 1716 determines the dragacceleration on mobile structure 101 caused by its relative motionwithin a body of water. The drag acceleration is combined with thecorrected thrust acceleration provided by combinatorial blocks 1712, aspart of a feedback loop, at block 1713.

In some embodiments, vessel dynamics block 1360 may also includereference frame conversion block 1718 configured to convert the expectedlinear velocity of mobile structure 101 provided by block 1714 (e.g.,which may be in a lateral/longitudinal local reference frame for mobilestructure 101) into an expected linear velocity as represented in anabsolute reference frame (e.g., east and north), which may be combinedwith the expected angular velocity of mobile structure 101 provided byblock 1714 and provided to integrator block 1720 to provide a positionand/or heading/orientation of mobile structure 101. The position and/orheading/orientation of mobile structure 101 is output by block 1360 andmay be fed back to blocks 1710 and 1718, as shown. As shown in FIG. 19,in some embodiments, reference frame conversion block 1718 may includevarious coordinate frame conversion blocks 1910, which may be configuredto convert linear velocities (e.g., in a relative coordinate frame) intolinear velocities in an absolute coordinate frame, based on a headingfor mobile structure 101, for further processing and/or output by frameconversion block 1718, as shown. In various embodiments, such conversionmay be implemented as a simple rotation, as shown in FIG. 19.

More generally, thrust controller 1330 and vessel dynamics block 1360(e.g., and/or vessel dynamics block 460) may in some embodiments besimplified (e.g., to omit disturbances and/or model errors) into acombined thrust dynamics block 2060 according to the representationillustrated by FIG. 20, for example, when control loop 1300 is used tomodel maneuvering of mobile structure 101. For example, in someembodiments, thrust dynamics block 2060 may include conversion block2010 configured to receive a controller or thrust demand (e.g., providedby position controller 1320 in FIG. 13) and provide a correspondingthrust acceleration. The thrust acceleration may be integrated by block2014 to provide an expected linear and angular velocity for mobilestructure 101, which is then output by thrust dynamics block 2060. Theexpected linear and angular velocity for mobile structure 101 may beprovided to motion damping block 2016, which may be configured todetermine a drag acceleration (e.g., related to drag force) on mobilestructure 101 caused by its relative motion within a body of water. Thedrag acceleration is combined with the thrust acceleration provided byblock 2010, as part of a feedback loop, at block 2012. In variousembodiments, the expected linear and angular velocity output by thrustdynamics block 2060 may be converted into a position and/or orientationof mobile structure 101 using techniques and blocks similar to blocks1718, 1720, and/or 1360 of FIGS. 17 and 19, for example, which may beused to provide appropriate outputs to measurement block 1370, as shownin FIG. 13.

As shown in FIG. 21, in embodiments where control loop 1300 is used tomodel maneuvering of mobile structure 101, measurement block 1370 mayinclude position transfer function blocks 2110, orientation transferfunction block 2112, angular velocity transfer function block 2114, andlinear velocity transfer function blocks 2116 each configured to model ameasurement delay and provide such measurement delayed positions,orientations, and/or velocities as output, which are then provided toposition controller 1320 to update the model. In some embodiments, thetransfer function blocks may be implemented as first order filters. Inembodiments where control loop 1300 is used to control maneuvering ofmobile structure 101, measurement block 1370 may instead include blocksconfigured to receive measured positions, orientations, and/orvelocities for mobile structure 101 (e.g., from sensors 140-148), whichmay be provided as output to position controller 1320 to proceed throughanother iteration of control loop 1300. In various embodiments,measurement block 1370 may include blocks configured to receive measuredpositions, orientations, and/or velocities for mobile structure 101 fromperimeter ranging system 148.

As shown in FIGS. 14 and 22, error block 1410 may be implemented asexecutable script and/or program code configured to receive targetmaneuvers and a current state for mobile structure 101, along withvarious other system parameters, and generate corresponding targetmaneuver errors, which may then be provided to controller demand blocks1420. For example, as shown in FIG. 22, error block 1410 may beconfigured to determine a target maneuver error by comparing a currentposition and/or orientation of mobile structure 101 to a position and/ororientation of the target maneuver (e.g., a target docking track) at apoint of closest approach to the target maneuver (e.g., which may beused to generate a position and/or orientation error), and thencomparing the current velocity of mobile structure 101 to a targetvelocity corresponding to the same point of closest approach. As shownin FIG. 23, in embodiments where the modeled maneuvering of mobilestructure 101 is to be plotted for display to a user, error block 1410may include initialization block 2300 (e.g., implemented in FIG. 23 asexecutable script and/or program code) configured to convert a targetmaneuver (e.g., a target docking track) represented by relatively fewwaypoints (e.g., 4, as would be typical for user input) into a targetmaneuver represented by larger number of waypoints (e.g., 1000) in orderto provide sufficient resolution for fine control/modeling ofmaneuvering of mobile structure 101.

FIG. 24 includes plots 2400 of various simulation parameters and controlsignals for docking assist system 100, in accordance with embodiments ofthe disclosure. For example, plot 2410 shows a target maneuver formobile structure 101 including a target docking track 2428 definedaccording to a starting position/orientation 2420, a target dockingposition/orientation 2426 at dock 222, and two waypoints 2422 2424disposed therebetween. Also shown along target docking track 2430 arecontroller demand indicators 2430 indicating a controller demand (e.g.,corresponding to a linear thrust for thrust controller 190) to maneuvermobile structure 101 along target docking track 2428. Plots 2412 showsplots of controller demands implementing target docking track 2428, andplots 2412 show plots of, from top to bottom, position, velocity, andheading error along target docking track 2428 while mobile structure 101is piloted according to the controller demands shown in plots 2412,along the same time base.

In accordance with various embodiments of the present disclosure,various control loop parameters, user inputs, sensor signals, controllersignals, and other data, parameters, and/or signals described inconnection with system 100 and/or control loops depicted in FIGS. 4-11and 13-21 may be stored at various points in the control loops,including within and/or during execution of any one of the blocks of aparticular control loop.

As described herein, embodiments of the disclosed robust controlautomatically compensate for drift from tide and wind, giving fastdisturbance rejection without destabilizing the control loop. However,such compensation can only be effective within the capability of thenavigation control system; for example, a sailboat without bow thrusterscannot always compensate for cross wind. As such, it may not be possibleto hold mobile structure 101 at a target position and/or orientation. Insome embodiments, a docking process may be flagged as complete whenmobile structure 101 is within predefined success tolerance range of atarget position and/or orientation (e.g., 20 cm, 0.5 degrees) and unableto maneuver closer to the target position and/or orientation.

Fast feedback robust control can require high bandwidth measurements,and gyroscope/accelerometer 144 may be configured to provide such highbandwidth measurements to complement perimeter ranging system 148.Resulting ranging to navigation hazards and/or relative velocities ofnavigational hazards may then be the result of fusion of perimeterranging system measurements and, for example, lateral accelerationmeasurements. Such fusion may be accomplished using various signalprocessing techniques, including fusion techniques employing Kalmanfilters, for example.

FIG. 25 illustrates a flowchart of a process 2500 to provide dockingassist for a mobile structure in accordance with an embodiment of thedisclosure. It should be appreciated that any step, sub-step,sub-process, or block of process 2500 may be performed in an order orarrangement different from the embodiments illustrated by FIG. 25. Forexample, in other embodiments, one or more blocks may be omitted from oradded to the process. Furthermore, block inputs, block outputs, varioussensor signals, sensor information, calibration parameters, and/or otheroperational parameters may be stored to one or more memories prior tomoving to a following portion of a corresponding process. Althoughprocess 2500 is described with reference to systems, processes, controlloops, and images described in reference to FIGS. 1A-24, process 2500may be performed by other systems different from those systems,processes, control loops, and images and including a different selectionof electronic devices, sensors, assemblies, mobile structures, and/ormobile structure attributes, for example.

In block 2502, docking assist parameters are received from a userinterface and perimeter sensor data is received from a perimeter rangingsystem. For example, controller 130 may be configured to receive dockingassist parameters from user interface 120 and perimeter sensor data fromperimeter ranging system 142.

In some embodiments, the docking assist parameters may include userpilot control signals, such as user input provided to user interface 120for direct navigational control of mobile structure 101. Such user inputmay include linear and/or rotational joystick user input, a dead stickuser input, and/or other direct user input to user interface 120. Inother embodiments, the docking assist parameters may include a targetdocking position and/or orientation for mobile structure 101. Forexample, controller 130 may be configured to generate a view of adocking area for mobile structure 101 on a display of user interface 120and receive user input from user interface 120 indicating a targetdocking track and/or a target docking position and/or orientation withinthe generated view of the docking area.

In block 2504, docking assist control signals are determined based ondocking assist parameters and perimeter sensor data. For example,controller 130 may be configured to determine one or more docking assistcontrol signals based, at least in part, on the docking assistparameters and the perimeter sensor data received in block 2502.

In some embodiments, where the docking assist parameters received inblock 2502 include user pilot control signals, controller 130 may beconfigured to determine a target linear and/or angular velocity formobile structure 101 based, at least in part, on the user pilot controlsignals and a maximum maneuvering thrust of the navigation controlsystem. Controller 130 may be configured to then determine the one ormore docking assist control signals based, at least in part, on thedetermined target linear and/or angular velocity, where the one or moredocking assist control signals are configured to cause navigationcontrol system 190 to maneuver mobile structure 101 according to thedetermined target linear and/or angular velocity. In relatedembodiments, the user pilot control signals may correspond to a deadstick user input, as described herein, and the target linear and/orangular velocity for mobile structure 101 may be set to zero.

In other embodiments, where the docking assist parameters received inblock 2502 include a target docking position and/or orientation formobile structure 101, controller 130 may be configured to determine atarget docking track for the mobile structure based, at least in part,on the target docking position and/or orientation and one or moredocking safety parameters corresponding to the target docking track. Infurther embodiments, the docking assist parameters received in block2502 may themselves include a target docking track. In eitherembodiments, controller 130 may be configured to then determine the oneor more docking assist control signals based, at least in part, on thedetermined or received target docking track, where the one or moredocking assist control signals are configured to cause navigationcontrol system 190 to maneuver mobile structure 101 according to thedetermined or received target docking track.

In additional embodiments, controller 130 may be configured to determinea range to a navigation hazard disposed within a monitoring perimeter ofthe perimeter ranging system based, at least in part, on the receivedperimeter sensor data, determine the range to the navigation hazard iswithin a safety perimeter for the mobile structure, and/or determine theone or more docking assist control signals based, at least in part, onthe determined range to the navigation hazard, wherein the one or moredocking assist control signals are configured to cause navigationcontrol system 190 to maneuver mobile structure 101 to evade thenavigation hazard by maintaining or increasing the range to thenavigation hazard.

In further embodiments, controller 130 may be configured to determine arelative velocity of a navigation hazard disposed within a monitoringperimeter of perimeter ranging system 148 based, at least in part, onthe received perimeter sensor data, to determine the relative velocityof the navigation hazard towards mobile structure 101 is greater than ahazard velocity limit, and determine the one or more docking assistcontrol signals based, at least in part, on the determined relativevelocity of the navigation hazard, wherein the one or more dockingassist control signals are configured to cause navigation control system190 to maneuver mobile structure 101 to evade the navigation hazard bydecreasing the relative velocity of the navigation hazard towards mobilestructure 101.

Controller 130 may also be configured to determine wind and/or watercurrent disturbances affecting navigation of mobile structure 101 and todetermine the one or more docking assist control signals based, at leastin part, on the determined wind and/or water current disturbances,wherein the one or more docking assist control signals are configured tocause navigation control system 190 to compensate for the determinedwind and/or water current disturbances while maneuvering mobilestructure 101 according to the received docking assist parameters.

In block 2506, docking assist control signals are provided to anavigation control system. For example, controller 130 may be configuredto provide the one or more docking assist control signals determined inblock 2504 to navigation control system 190. In some embodiments,navigation control system 190 may include one or more of steeringactuator 150, propulsion system 170, and thrust maneuver system 172, andproviding the docking assist control signal to navigation control system190 may include controlling steering actuator 150, propulsion system170, and/or thrust maneuver system 172 to maneuver mobile structure 101according to a target linear and/or angular velocity or a target dockingposition and/or orientation corresponding to docking assist parametersreceived in block 2504.

For example, controller 130 may be configured to control steeringactuator 150, propulsion system 170, and/or thrust maneuver system 172of mobile structure 101 to generate a target linear and/or angularvelocity for mobile structure 101 identified in the docking assistparameters provided in block 2504. If the target linear and/or angularvelocity is zero (e.g., corresponding to a dead stick user input), thenthe docking assist control signals may be configured to counteract anydetected motion of mobile structure 101, including motion caused byvarious external disturbances, as described herein. In another example,controller 130 may be configured to control steering actuator 150,propulsion system 170, and/or thrust maneuver system 172 of mobilestructure 101 to follow a target docking track to a target dockingposition and/or orientation identified in the docking assist parametersprovided in block 2504.

In some embodiments, controller 130 may be configured to provide dockingassist control signals configured to evade a navigation hazard detectedby perimeter ranging system 190 by maintaining or increasing a range tothe navigation hazard and/or by decreasing the relative velocity of thenavigation hazard towards mobile structure 101. In such embodiments, thedocking assist control signals may be configured to minimize deviationfrom the target linear and/or angular velocity, or to minimize deviationfrom the target docking track, while evading the navigation hazard.

Embodiments of the present disclosure can thus provide reliable andaccurate docking assist for mobile structures. Such embodiments may beused to provide assisted and/or fully autonomous docking and/ornavigation of a mobile structure and may assist in the operation ofother systems, devices, and/or sensors coupled to or associated with themobile structure, as described herein.

Navigation control systems, such as navigation control system 190 inFIG. 1A, sometimes employ a joystick or other manual user interface,typically as part of a thrust maneuver system (e.g., similar to thrustmaneuver system 172 of FIG. 1A) to provide additional degrees of freedom(e.g. sliding a vessel from side to side or rotating on the spot) notusually afforded by a conventional helm and throttle. These manual userinterfaces may employ a number of non-linear characteristics to make theinput more accessible to a human operator, such as a null zone or deadzone in the center of a joystick control range, in which joystickmovement/manipulation below a certain deflection threshold is ignored.

Typically, joysticks and other types of manual user interfaces employcontrol signal techniques and cabling that present a convenientelectrical interface with which to couple a docking assist system and/orautopilot to control a vessel programmatically. However, the variousdeliberate non-linear characteristics of such manual user interfaces canrender programmatic control through manipulation of such control signalsa considerably complex problem, especially when, for example, thecharacteristics of a particular manual user interface's null zone areunknown or undocumented. Embodiments described herein present amethodology capable of characterizing and adaptively compensating for aninitially-unknown null zone and/or other non-linearity of a 3rd-party(and therefore black-box) joystick/manual user interface, allowing adocking assist system/autopilot to “see” a navigation control systemwith no null zone and to interface transparently with the navigationcontrol system.

Without null zone compensation, a docking assist system or autopilotwill attempt to apply engine thrust on demand, yet because the controlsignal may still be within the null zone of the joystick/manual userinterface, the engines/thrusters may not respond. The docking assistsystem may then overcompensate, causing a discrepancy between therequested and applied thrust when the control signal eventually leavesthe null zone, which will hamper the ability of the docking assistsystem to control the vessel. It will also present a significant latencyas the docking assist system tries to move the vessel by generatingcontrol signals within the null zone with no initial reaction from theengines/thrusters, which will significantly reduce the ability of thedocking assist system to make fine or rapid adjustments. As such, thenull zone deliberately imposed upon a joystick/manual user interface foroperator comfort can have a detrimental impact on the ability of adocking assist system or autopilot to control a vessel programmatically.Embodiments described herein adaptively characterize and compensate forsuch non-linearities, thereby facilitating assisted or autonomouscontrol of a vessel via such manual user interfaces.

In general, null zone compensation can be implemented in three stages:null zone characterization, null zone boundary initialization, and nullzone compensation (e.g., used to supplement and/or replace controlsignals provided by a manual user interface, such as a joystick). In oneembodiment, null zone characterization may be performed by instructing auser (e.g., through graphics and/or text displayed on a display of userinterface 120) to manipulate such joystick through a null zone boundaryat different points along the null zone boundary in order to determine aset of null zone transition points between the null zone and theoperative zone of the joystick and/or the control signals of thejoystick. Each null zone transition point is typically represented as atwo dimensional point in Cartesian space (e.g., X deflection, Ydeflection) that represents a particular joystick position or a joystickcontrol signal corresponding to that particular position.

In another embodiment, a docking system/autopilot configured to sensefeedback of operation of navigation control system 190 (e.g., throughengine/thruster sensors and/or through motion sensors, such as sensors140-148 shown in FIG. 1) may be configured to perform an exhaustivesearch of such control signals/joystick positions, to determine arelatively complete set of such null zone transition points. Such nullzone transition points may then be used to describe a null zone boundarysegregating null zone control signals/joystick positions within the nullzone from operative zone control signals/joystick positions equal to oroutside the null zone boundary.

In various embodiments, null zone boundary initialization may refer toany of a number of different techniques to convert an acquired set ofnull zone transition points for a joystick/manual user interface into aset of straight line segments that, when combined,characterize/represent a null zone boundary. For example, the null zonetransition points may be converted to polar form (e.g., rho, theta)about the center/neutral position of a characterized joystick (and/orthe corresponding control signal), and then sorted by theta. Thissorting allows neighboring null zone transition points to be joinedtogether to create a set of null zone boundary line segments thatrepresent a continuous and well defined function with only one value forrho for each theta. Such null zone boundary line segments may beindividually characterized by a set of two null zone transition pointsthat constitute the boundary of each null zone boundary line segment,and the thetas of the polar form of the two null zone transition points.Null zone boundary line segments may be linked together so as to becontinuous (e.g., such that the “end” marker of segment n is equal tothe “start” marker of segment n+1). Thus, a list of null zone boundaryline segments may be created in the form [XStart, YStart, XEnd, YEnd,ThetaStart, ThetaEnd].

Sometimes one null zone boundary line segment will cross the theta=0degrees boundary, and as such its ThetaEnd (being after 0 degrees) maybe less than its ThetaStart (which will be just before 360 degrees). Theintention is that given an arbitrary joystick position/control signal inpolar form, a corresponding null zone boundary line segment can bechosen based on whether the theta of the joystick position/controlsignal falls between ThetaStart and ThetaEnd for a given null zoneboundary line segment. With this in mind, the zero crossing segment canbe duplicated within the list such that ThetaEnd of one+=360, andThetaStart of the other 360, resulting in a pair of null zone boundaryline segment that cover all cases around the zero crossing (e.g.,ranging from −10 to 10 degrees and 350 to 370 degrees, for example),regardless of how a particular joystick position/control signal isconverted to polar form. Alternatively, ThetaEnd of one can be set to360, and ThetaStart of the other to 0 to achieve the same effect.

In various embodiments, null zone compensation may refer to any of anumber of different techniques to use an initialized/characterized nullzone boundary to convert joystick deflections and/or correspondingcontrol signals to null zone compensated control signals. For example, araw joystick deflection/input control signal may be received andconverted into polar form (e.g., [rhoIn, thetaIn], as described herein.ThetaIn of the raw input control signal may be compared to the alreadygenerated list of null zone boundary line segments in order to determinea particular null zone boundary line segment in which thetaIn resides(e.g., thetaIn is within range of ThetaStart and ThetaEnd of thatparticular null zone boundary line segment). ThetaIns that equalThetaStart or ThetaEnd of a neighboring pair of null zone boundary linesegments may be assigned to either null zone boundary line segment. Rhoequal to zero may be treated as a special case and assigned a null zonecompensated control signal/joystick position of [0,0].

In various embodiments, an intersection point between the correspondingdeflection vector (e.g., [0, 0; Joystick_deflection_x,Joystick_deflection_y]) and the identified null zone boundary linesegment (e.g., [XStart YStart; XEnd YEnd]) may be determinedgeometrically, and the intersection point may be representedin/converted to polar form (e.g., [rhoInter, thetaInter]). Subsequently,an operative zone width along the theta of the raw deflection/controlsignal may be determined, where the operative zone width corresponds tothe distance between the intersection point and a correspondingoperative zone boundary point, at which a line through the origin ([00]) and the intersection point intersects the “frame” of the manual userinterface (e.g., the maximum deflection/control signal space in whichthe joystick can operate, sometimes represented by [−1 1; −1 1]). Suchoperative zone boundary point (e.g., rhoEdge, thetaEdge]) corresponds toeffectively the greatest possible value for rho at the given theta ofthe raw deflection/control signal. Thus, the distance from theorigin/neutral position/deflection/control signal to the boundary of thenull zone is known, and the distance from the origin to the frameboundary along the theta of the raw joystick deflection is also known.Such values may be used to determine the corresponding null zonecompensated control signals.

For example, in one embodiment, the following method, represented inpseudocode, may be used to perform null zone compensation (e.g., whererhoDeadMin defines the size of a synthetic control signal damping zoneimposed/presented to the control system to allow tiny variations in thecontrol signals about [0 0] to be permitted without causing wild jumpsin the navigation control system response; in a true null zone suchvariations would be forced to zero and therefore not impact functioningof thrust maneuver system 172; the pseudo synthetic control signaldamping zone prevents instability or other operational issues in somesystems that might otherwise be caused by a tiny amount of input noiseabout [0 0], yet retains enough sensitivity to reliably controloperation of thrust maneuver system 172).

if rhoIn >= rhoDeadMin  rhoProportionalOutsideDeadzone = (rhoIn -rhoDeadMin) / (rhoEdge - rhoDeadMin);  rhoOut = rhoInter + (rhoEdge -rhoInter) * rhoProportionalOutsideDeadzone;  else rhoProportionalInsideDeadzone = rhoIn / rhoDeadMin;  rhoOut =rhoProportionalInsideDeadzone * rhoInter;  end

Once rhoOut is determined, [rhoOut, thetaIn] may be converted toCartesian coordinates to provide the corresponding null zone compensatedcontrol signal (e.g., corresponding to an XY joystick deflection/controlsignal). Null zone characterization and initialization may be performedonce or periodically (e.g., if the null zone for the particular manualuser interface might change over time), and null zone compensation istypically performed at the rate control signals are generated by thejoystick/manual user interface.

In various embodiments, such null zone compensation may be used in bothassisted and autonomous maneuvering of a vessel. For example, if a useris maneuvering mobile structure 101 using joystick 120, and system 100is assisting in such maneuvering by converting manual joystick inputsand their corresponding control signals into velocity demands, asdescribed herein, the described null zone compensation may be used tocompensate for any null zone integrated with or between, for example,joystick 120 and thrust maneuver system 172, so as to provide a moreintuitive and response control over maneuvering of mobile structure 101,and/or to slow or stop mobile structure 101 if approaching a dock ornavigation hazard, as described herein. If system 100 is maneuveringmobile structure 101 autonomously, such as for autonomous dockingassistance, the described null zone compensation may be used tocompensate for any null zone integrated with thrust maneuver system 172,so as to allow for reliable and accurate control of propulsion system170, thrust maneuver system 172, and/or other elements of navigationcontrol system 190 and/or system 100.

FIG. 26 illustrates a block diagram of a docking assist system 2600(e.g., user interface/controller 120/130, with one or more additionalelements of system 100 shown in FIG. 1A) integrated with a thrustmaneuver system 2672 in accordance with an embodiment of the disclosure.As shown in FIG. 26, thrust maneuver system 2672 includes joystick 2620providing corresponding joystick control signals over control signalline 2622 to propulsion system 2670, similar to joystick 120 providingcontrol signals to elements of navigation control system 190, asdescribed herein. Generally, thrust maneuver system 2672 may beimplemented similarly to thrust maneuver system 172 of FIG. 1A. Invarious embodiments, propulsion system 2670, which may be implemented asan articulated and/or multi-thruster thruster propulsion system, forexample, may include a control signal interface 2671, which may beconfigured to receive control signals from joystick 2622 and controlpropulsion system 2670 to implement navigation maneuvers correspondingto the control signals, as described herein. Either or both joystick2620 and control signal interface may include a null zone in whichphysical manipulation and/or corresponding control signals do not changeoperation of propulsion system 2670 (e.g., to the extent that it wouldaffect maneuvering of mobile structure 101, for example). Null zonecompensation, as described herein, may be used to compensate for suchnull zone(s), regardless of where they reside within thrust maneuversystem 2672.

Also shown in FIG. 26 is user interface 120/controller 130 (e.g., fromFIG. 1A) coupled to control signal line 2622 through autopilot/controlsignal coupling 2635. In various embodiments, control signal coupling2635 may be configured to selectively transmit control signals generatedby joystick 2620 to controller 130 over controller line 2632, pass orrelay control signals generated by joystick 2620 to propulsion system2670 over control signal line 2622, block control signals generated byjoystick 2620 from reaching propulsion system 2670, and/or to replace ormodify control signals generated by joystick 2620 according to controlsignals generated by controller 130 and provided over controller line2632, all as controlled by controller 130 over controller line 2632. Assuch, control signal coupling 2635 allows components of docking assistsystem 100 (e.g., user interface 120, controller 130, and/or other suchcomponents) to be linked and/or communicate with and control elements ofnavigation control system 190, including thrust maneuver system 2672,without having to substantially alter or replace joystick 2620, controlsignal interface 2671, and/or propulsion system 2670. More generally,controller 130 may be configured to implement any of the processesdescribed herein, including providing null zone compensation for thrustmaneuver system 2672. Control signal line 2622 may be implementedaccording to any wired and/or wireless communication protocol orcombination of protocols, for example, including one or multiple CANbuses and/or interconnects.

FIGS. 27-29 illustrate null zone transfer functions in accordance withembodiments of the disclosure. For example, FIGS. 27-29 each showidentified null zone transition points 2720 (marked ‘o’), derived nullzone boundary segments 2722 (marked with lines) and a linearly spacedsampling 2730 (marked ‘x’) of the transfer function implementedaccording to the methodology described herein, given three differentexample null zones 2710, 2810, 2910, and three corresponding operationalzones 2740, 2840, and 2940. Crucially, the number of sample points 2730that fall within each null zone 2710, 2810, 2910 is minimized in amanner controlled by “rhoDeadMin.” As shown in FIGS. 27-29, null zone2710 corresponds to an octagonal shape, null zone 2810 corresponds to asquare shape, and null zone 2910 corresponds to a circular or ellipticalshape, and embodiments are able to compensate for each shape using themethodology described herein.

FIG. 30 illustrates a flow diagram of a process 3000 to provide nullzone compensation for a docking assist system in accordance with anembodiment of the disclosure. It should be appreciated that any step,sub-step, sub-process, or block of process 3000 may be performed in anorder or arrangement different from the embodiments illustrated by FIG.30. For example, in other embodiments, one or more blocks may be omittedfrom or added to the process. Furthermore, block inputs, block outputs,various sensor signals, sensor information, calibration parameters,and/or other operational parameters may be stored to one or morememories prior to moving to a following portion of a correspondingprocess. Although process 3000 is described with reference to systems,processes, control loops, and images described in reference to FIGS.1A-29, process 3000 may be performed by other systems different fromthose systems, processes, control loops, and images and including adifferent selection of electronic devices, sensors, assemblies, mobilestructures, and/or mobile structure attributes, for example.

In block 3002, a null zone corresponding to a manual user interface ischaracterized. For example, controller 130 may be configured tocharacterize null zone 2710 corresponding to manual userinterface/joystick 2620. In one embodiment, controller 130 may beconfigured to display instructions to a user on a display of userinterface 120 instructing the user to manipulate joystick 2620 todetermine a set of null zone transition points 2720 distributed about aboundary (e.g., null zone boundary line segments 2722) of null zone2710. For example, controller 130 may be configured to monitor controlsignals from joystick 2620 over control signal line 2622 to determine aset of null zone transition points corresponding to a null zoneimplemented by joystick 2620.

In another embodiment, controller 130 may be configured to receive oneor more operational feedback signals corresponding to operation ofthrust maneuver system 2672, such as detecting motion of mobilestructure 101 (e.g., sensed by sensors 140-148), or detecting start up,throttle, thrust pressure, and/or other operational states of thrustmaneuver system 2672, to determine a set of null zone transition pointscorresponding to a null zone implemented by control signal interface2671 and/or joystick 2620. In a further embodiment, controller 130 maybe configured to generate control signals and provide them to thrustmaneuver system 2672 directly to determine a set of null zone transitionpoints corresponding to a null zone implemented by control signalinterface 2671 and/or thrust maneuver system 2672.

In block 3004, a null zone boundary corresponding to the null zonecharacterized in block 3002 is initialized. For example, controller 130may be configured to convert the set of null zone transition points 2720identified in block 3002 for joystick/manual user interface 2620 into aset of null zone boundary line segments 2722 that, when combined,characterize/represent a null zone boundary corresponding to null zone2710, as described herein. In various embodiments, such null zoneboundary may be characterized by a list of such null zone boundary linesegments that together represent a continuous and single valued functioncorresponding to the null zone boundary. The set or list of null zoneboundary line segments may be differentiated from one another by thepolar angles of their end points relative to a neutral position forjoystick/manual user interface 2620.

In block 3006, null zone compensated control signals are generated. Forexample, in some embodiments, controller 130 may be configured toreceive raw joystick control signals from joystick 2620, convert the rawjoystick control signals into null zone compensated control signalsbased on the null zone boundary initialized in block 3004, and providethe compensated control signals to thrust maneuver system 2672. In otherembodiments, controller 130 may be configured to determine a thrust orother navigation control demand, convert that demand into a raw controlsignal corresponding to a raw control signal generated by joystick 2620if used to implement the demand, convert the raw control signal into anull zone compensated control signal based on the null zone boundaryinitialized in block 3004, and provide the compensated control signal tothrust maneuver system 2672.

Embodiments of the present disclosure can use such techniques to provideadaptive, reliable, and accurate docking assist and/or other types ofnavigational control for mobile structures, for example, and can do sorelatively inexpensively by leveraging already-installed navigationcontrol systems and related cabling and control signal techniques, asdescribed herein.

For example, in some embodiments, system 2600 in FIG. 26 may beimplemented more generally as an autopilot system 2600 (e.g., userinterface/controller 120/130, with one or more additional elements ofsystem 100 shown in FIG. 1A) configured to adaptively integrate withthrust maneuver system 2672 and/or any other portion of navigationcontrol system 190 to provide various types of autopilot functionalityover control signal line 2622 disposed between manual userinterface/joystick 2622 and control signal interface 2671, which may beconfigured to interface with propulsion system 2670, as shown in in FIG.26, and/or any other element of navigation control system 190 (e.g.,steering sensor/actuator 150, propulsion system 170, and/or thrustmaneuver system 172), as described herein. As noted herein, controlsignal coupling 2635 may be configured to selectively transmit controlsignals generated by joystick 2620 to controller 130 over controllerline 2632 (e.g., allowing controller 130 to monitor such controlsignals), pass or relay control signals generated by joystick 2620 topropulsion system 2670 over control signal line 2622, block controlsignals generated by joystick 2620 from reaching propulsion system 2670,and/or to generate, replace, or modify control signals generated byjoystick 2620 according to control signals generated by controller 130and provided over controller line 2632, all as controlled by controller130 over controller line 2632. As such, controller 130 and controlsignal coupling 2635 may be configured to emulate at least a portion ofthe typical operation of manual user interface/joystick 2622 withrespect to control signaling generated along control signal line 2622,such as in response to user input provided to manual userinterface/joystick 2622, as described herein.

In particular, user interface/controller 120/130 may be configured todetermine a maneuvering protocol governing how control signalscommunicated between manual user interface 2620 and control signalinterface 2671 over control signal line 2622 cause propulsion system2670 to maneuver mobile structure 101. In various embodiments, suchlearning process may be performed without any prior knowledge of themaneuvering protocol, for example, which allows userinterface/controller 120/130 and control signal coupling 2635 to becoupled into any thrust maneuver system 2672, regardless of manufactureror particular type or implementation of maneuvering protocol, manualuser input 2620, control signal interface 2671, control signal line2622, and/or propulsion system 2670.

In some embodiments, user interface/controller 120/130 may be configuredto identify and/or modify only maneuvering signals generated by manualuser interface 2620 (e.g., control signals corresponding to or generatedby direct manual manipulation of manual user interface 2620, as opposedto handshake, device ID, frame ID, diagnostic, and/or other portions ofthe control signals communicated between manual user interface 2620 andcontrol signal interface 2671), so as to eliminate the unnecessary(e.g., and typically relatively lengthy, complex, and error prone)learning of the full communication protocol governing control signalscommunicated between manual user interface 2620 and control signalinterface 2671. Non-maneuvering signals may be relayed over controlsignal line 2622 and/or replicated by user interface/controller 120/130and/or control signal coupling 2635. In various embodiments, a resultingmaneuvering protocol may be used to control operation of thrust maneuversystem 2672 and/or other portions of navigation control system 190, suchas providing docking assist control signals (e.g., for docking assistand/or autonomous dockings) and/or other navigational control, asdescribed herein.

In a particular embodiment, control signal line 2622 may be implementedby multiple CAN buses (e.g., 2 or more) between manual userinput/joystick 2620 and control signal interface 2671 of propulsionsystem 2670. Control signal line 2622 may be configured to conveyjoystick deflection (e.g., how far joystick 2620 has been manuallypushed by a user) along with other (e.g., typically unknown) data ascontrol signals on the multiple CAN buses (e.g., similar to an opensystems interconnection (OSI) layer 2 hub). Control signal coupling 2635may be implemented with multiple dual-CAN bus interfaces so as to becoupled between manual user input/joystick 2620 and control signalinterface 2671 of propulsion system 2670 across each of the multiple CANbuses of control signal line 2622. In various embodiments, userinterface/controller 120/130 and/or control signal coupling 2635 (e.g.,which may be implemented with one or more microcontrollers and/or otherlogic devices) may be configured to bidirectionally relay CAN framesacross each dual-CAN bus interface, such that control signals/trafficcan flow freely in both directions as if control signal coupling 2635was absent from system 2600. If necessary for a particularimplementation and/or application, a CAN terminator may be insertedand/or coupled to one or both sides of one or more dual-CAN businterfaces of control signal coupling 2635.

In such embodiment, user interface/controller 120/130 may be configuredto use control signal coupling 2635 to monitor control signals on thevarious CAN buses of control signal line 2622 and identify the ID,format, and/or other characteristics of CAN bus frames or messagescontaining joystick deflection data. For example, controller 130 may beconfigured to use a display or speaker of user interface 120 to instructa user to manually manipulate joystick 2620, such as according to aparticular learning pattern or deflection direction and/or magnitude,for example, and to identify frames and/or portions of the frames thatchange when joystick 2620 is manipulated according to the providedpattern or deflection direction. In another example, controller 130 maybe configured to identify the absence of such frames and/or portions offrames while joystick 2620 is disconnected from control signal line 2622(e.g., by a user instructed to do so by user interface 120). Once suchframes or portions of frames are identified as maneuvering signals,controller 130 may be configured to generate modified maneuveringsignals and insert them within the frames or portions of frames on theCAN buses to control operation of propulsion system 2670, for example.In a specific example of control using a learned maneuvering protocol(e.g., CAN frame ID containing joystick deflection data, magnitude/signof possible joystick deflections, as reflected in the joystickdeflection data, and/or correlation of such data with navigationalresults/maneuvering of mobile structure 101), controller 130 and/orcontrol signal coupling 2635 may be configured to implement softwareinstructions and/or logic similar to the following pseudocode:

 Given BusJ = Joystick Port,  Given BusE = Engine Port,  Given InputID =CAN ID of joystick message containing joystick deflection (message  tomodify),  Given HIDData = Manual joystick deflection,  GivenModifiedData = Controller-modified joystick deflection, do:while(BusJ.readFrames( )) - if (BusJFrame.ID == InputID) - - HIDData =BusJFrame.Data - - BusJFrame.Data = ModifiedData - RelayFrames(From BusJto BusE) - If (BusE.readSingleFrame( )) - - RelaySingleFrame(From BusEto BusJ) // (avoids locking the system in the event of bandwidth spikesin traffic in one direction) while(BusE.readFrames( )) -RelayFrames(From BusE to BusJ) - If (BusJ.readSingleFrame( )) - -RelaySingleFrame(From BusJ to BusE) // (avoids locking the system in theevent of bandwidth spikes in traffic in one direction) if(NewModifiedDataReceived) // (updated controller-modified joystickdeflection?) - ModifiedData = NewModifiedData TransmitToHost(HIDData) //(optionally send manual joystick deflection to controller) loop.

The above pseudocode/logic relays all non-maneuvering (but possiblyessential) control signal traffic using the general logic andcommunication protocol already implemented in joystick 2620 and controlsignal interface 2671, and all that is modified is the joystickdeflection itself (e.g., the maneuvering signals), according to alearned maneuvering protocol. In various embodiments, the abovepseudocode/logic, control signal coupling 2635, and/or controller 130may be configured to maintain any specific timings of transmissions ofCAN messages/control signals (e.g., typically difficult to reproduceaccurately in a full emulation) by relying on the learned and provenimplementation already present in thrust maneuver system 2672, as shown.For example, the communication of ModifiedData to control signalcoupling 2635 may be asynchronous with the timing of CAN frames alongcontrol signal line 2622, which may be maintained by control signalcoupling 2635 as it inserts ModifiedData into BusJFrame.Data and relaysframes from BusJ to BusE.

Under some relatively extreme field conditions, there is a risk thatcontroller line 2632 between controller 130 and control signal coupling2635 may become disconnected or damaged, for example, or that controller130 may otherwise fail to provide an updated ModifiedData to controlsignal coupling 2635 during operation of thrust maneuver system 2672. Ifsuch failure is left undetected, thrust maneuver system 2672 mayrepeatedly supply an old and substantially constant modified joystickdeflection (e.g., as a modified CAN bus frame/control signals) tocontrol signal interface 2671, which can essentially lock propulsionsystem 2670 in a powered state that cannot be overridden by additionalmanual input provided to joystick 2620 and that can result in damage tomobile structure 101 and/or surrounding structures.

In some embodiments, to address this risk, controller 130 and/or controlsignal coupling 2635 may be configured to send and receive modifiedjoystick deflections according to a preselected or individualized orotherwise known maximum time interval. Control signal coupling 2635 maybe configured to detect that the maximum time interval for a particularreceived modified joystick deflection has been exceeded and to enter asafe-fail mode. For example, such safe-fail mode may include settingModifiedData to a default value (e.g., zero joystick deflection),relaying HIDData without modification to control signal interface 2671(e.g., setting ModifiedData equal to HIDData), and/or generating avisible and/or audible alert via user interface 120 to notify a user ofmobile structure 101 that assisted and/or autonomous navigation ofmobile structure 101 via control line 2632 and/or control signalcoupling 2635 has failed.

FIG. 31 illustrates a flow diagram of a process 3100 to determine amaneuvering protocol for navigation control system 190 in accordancewith an embodiment of the disclosure. It should be appreciated that anystep, sub-step, sub-process, or block of process 3100 may be performedin an order or arrangement different from the embodiments illustrated byFIG. 31. For example, in other embodiments, one or more blocks may beomitted from or added to the process. Furthermore, block inputs, blockoutputs, various sensor signals, sensor information, calibrationparameters, and/or other operational parameters may be stored to one ormore memories prior to moving to a following portion of a correspondingprocess. Although process 3100 is described with reference to systems,processes, control loops, and images described in reference to FIGS.1A-30, process 3100 may be performed by other systems different fromthose systems, processes, control loops, and images and including adifferent selection of electronic devices, sensors, assemblies, mobilestructures, and/or mobile structure attributes, for example.

In block 3102, control signals communicated between a manual userinterface and a navigation control system for a mobile structure aremonitored. For example, controller 130 may be configured to use controlsignal coupling 2635 to monitor control signals communicated betweenmanual user interface/joystick 2620 and control signal interface 2671 ofpropulsion system 2670. In some embodiments, control signal coupling2635 may be configured to relay control signals, such as CAN bus framesand/or portions of frames transmitted by manual user interface/joystick2620 and/or control signal interface 2671 along control signal line 2622to controller 130 across controller line 2632. Controller 130 mayreceive the control signals and process the control signals to identifyand/or extract control data, timing, and/or other control signalcharacteristics from the control signals, which may be stored and/oraggregated for further analysis and/or replay to manual user interface2620 and/or control signal interface 2671 using control signal coupling2635, for example.

In block 3104, maneuvering signals generated by a manual user interfaceare identified. For example, controller 130 may be configured toidentify maneuvering signals generated by manual user interface/joystick2620 based, at least in part, on the control signals monitored in block3102. In one embodiment, controller 130 may be configured to displayinstructions to a user on a display of user interface 120 instructingthe user to manipulate manual user interface 2620 according to one ormore predefined learning patterns, deflection directions, and/ordeflection magnitudes of manipulations of manual user interface 2620,for example, and to identify control signals (e.g., monitored in block3102) that change according to such predefined learning patterns asmaneuvering signals. For example, controller 130 may be configured toidentify a set of maneuvering signals in the control signals monitoredin block 3102 corresponding to such manipulations of manual userinterface 2620.

In another embodiment, controller 130 may be configured to receive oneor more operational feedback signals corresponding to operation ofthrust maneuver system 2672, such as detecting motion of mobilestructure 101 (e.g., sensed by sensors 140-148), or detecting start up,throttle, thrust pressure, and/or other operational states of thrustmaneuver system 2672, to determine a set of maneuvering signals in thecontrol signals monitored in block 3102 corresponding to such knownmanipulations of manual user interface 2620. In a further embodiment,controller 130 may be configured to generate control signals and providethem to thrust maneuver system 2672 directly to determine a set ofmaneuvering signals corresponding to manipulations of manual userinterface 2620.

In block 3106, a maneuvering protocol corresponding to a manual userinterface is determined. For example, controller 130 may be configuredto determine a maneuvering protocol corresponding to manual userinterface/joystick 2620 based, at least in part, on the maneuveringsignals identified in block 3104. In one embodiment, controller 130 maybe configured to determine the maneuvering protocol that issubstantially the same as the maneuvering signals identified in block3104, such that use of the maneuvering protocol includes replayingmaneuvering signals identified in block 3104 to effect maneuvering ofmobile structure 101. For example, controller 130 may be configured toretrieve stored maneuvering signals identified in block 3104 and usecontrol signal coupling 2635 to generate and/or transmit control signalsmimicking the identified maneuvering signals (e.g., to control signalinterface 2671 of propulsion system 2670).

In another embodiment, controller 130 may be configured to determine amaneuvering protocol, based on the maneuvering signals identified inblock 3104, including a mapping of a range of manipulation values to arange of possible manipulations of manual user interface 2620 and/or arange of accelerations and/or velocities of mobile structure 101 (e.g.,as caused by propulsion system 2670 controlled by manual user interface2620), such that use of the maneuvering protocol includes using suchmapping to determine a manipulation value corresponding to a desiredmaneuver of mobile structure 101. For example, controller 130 may beconfigured to use control signal coupling 2635 to generate and/ortransmit control signals corresponding to such determined manipulationvalue (e.g., to control signal interface 2671 of propulsion system2670). In embodiments where control signal line 2622 is implemented asone or more CAN buses, controller 130 and/or control signal coupling2635 may be configured to generate and/or transmit CAN bus frames withmodified manual user interface deflections along control signal line2622 (e.g., to control signal interface 2671), for example, or toreplace manual user interface deflections in CAN bus frames transmittedalong control signal line 2622 with modified manual user interfacedeflections, according to the determined maneuvering protocol, and asdescribed herein.

Embodiments of the present disclosure can use such techniques to provideadaptive, reliable, and accurate docking assist and/or other types ofnavigational control for mobile structures, for example, and can do sorelatively inexpensively by leveraging already-installed navigationcontrol systems and related cabling and control signal techniques, asdescribed herein.

FIG. 32 illustrates a flow diagram of a process 3200 to provideautonomous and/or assisted navigational control for mobile structure 101in accordance with an embodiment of the disclosure. It should beappreciated that any step, sub-step, sub-process, or block of process3200 may be performed in an order or arrangement different from theembodiments illustrated by FIG. 32. For example, in other embodiments,one or more blocks may be omitted from or added to the process.Furthermore, block inputs, block outputs, various sensor signals, sensorinformation, calibration parameters, and/or other operational parametersmay be stored to one or more memories prior to moving to a followingportion of a corresponding process. Although process 3200 is describedwith reference to systems, processes, control loops, and imagesdescribed in reference to FIGS. 1A-31, process 3200 may be performed byother systems different from those systems, processes, control loops,and images and including a different selection of electronic devices,sensors, assemblies, mobile structures, and/or mobile structureattributes, for example.

In block 3202, control signals communicated between a manual userinterface and a navigation control system for a mobile structure aremonitored. For example, controller 130 may be configured to use controlsignal coupling 2635 to monitor control signals communicated betweenmanual user interface/joystick 2620 and control signal interface 2671 ofpropulsion system 2670, similar to block 3102 of process 3100 in FIG.31. In some embodiments, control signal coupling 2635 may be configuredto relay control signals, such as CAN bus frames and/or portions offrames transmitted by manual user interface/joystick 2620 and/or controlsignal interface 2671 along control signal line 2622 to controller 130across controller line 2632. Controller 130 may receive the controlsignals and process the control signals to identify and/or extractcontrol data, timing, and/or other control signal characteristics fromthe control signals, which may be stored and/or aggregated for furtheranalysis and/or replay to manual user interface 2620 and/or controlsignal interface 2671 using control signal coupling 2635, for example.

In block 3204, a navigation mode for a mobile structure is determined.For example, controller 130 may be configured to determine a navigationmode for mobile structure 101 based on one or more of a user selectionprovided to user interface 120, a monitored environmental state ofmobile structure 101 and/or an operational state of system 100, and/or aprior navigation mode for mobile structure 101. In some embodiments, thenavigation mode may include one or more of a navigation assist mode, anautopilot or autonomous navigation mode, a manual navigation mode,and/or other navigation and/or docking modes, as described herein.

For example, a navigation assist mode may correspond to a configurationof system 100 where a mixture of manual input provided to manual userinterface 2620 and modified control signals generated by controller 130are used to pilot mobile structure 101, such as in a docking assistmode, as described herein. An autopilot or autonomous navigation modemay correspond to a configuration of system 100 where primarily controlsignals generated by controller 130 are used to pilot mobile structure101, such as in an autonomous docking mode, as described herein. Whilein such mode, manual input applied to manual user interface 2620 may beused to exit such mode and enter a manual navigation mode, where controlsignals generated by manual user interface 2620 are primarily relayed tocontrol signal interface 2671. In various embodiments, each navigationmode may include generating null zone compensated control signals so asto compensate for null zone associated with manual user interface 2620and/or control signal interface 2671, as described herein (e.g., evenwhen in manual navigation mode).

In block 3206, control signals are selectively relayed, blocked, ormodified. For example, controller 130 may be configured to selectivelyrelay, block, or modify (e.g., replace existing, modify existing, and/orgenerate new, inclusively) control signals monitored in block 3202based, at least in part, on the navigation mode for mobile structure 101determined in block 3204. In various embodiments, controller 130 may beconfigured to modify control signals monitored in block 3202 based, atleast in part, on a learned or determined maneuvering protocol, such asthe maneuvering protocol determined in block 3106 of process 3100.

In embodiments where the determined navigational mode is the navigationassist mode, controller 130 may be configured to use control signalcoupling 2635 to generate and/or transmit modified control signals basedon the control signals monitored in block 3202 (e.g., generated bymanual user interface 2620) and the maneuvering protocol determined inblock 3106, similar to and/or including the docking assist controlsignals provided in block 2506 of process 2500 in FIG. 25. Inembodiments where the determined navigational mode is the autopilot orautonomous navigation mode, controller 130 may be configured to usecontrol signal coupling 2635 to generate and/or transmit control signalsbased on the maneuvering protocol determined in block 3106, similar toand/or including the docking assist/autonomous docking control signalsprovided in block 2506 of process 2500 in FIG. 25. In embodiments wherethe determined navigational mode is the manual navigation mode,controller 130 may be configured to use control signal coupling 2635 torelay control signals generated by manual user interface 2620.

In any of such embodiments and/or modes, controller 130 may beconfigured to use control signal coupling 2635 and/or the maneuveringprotocol determined in block 3106 to modify such control signals tocompensate for a null zone associated with manual user interface 2620and/or control signal interface 2671. Moreover, in any of suchembodiments and/or modes, controller 130 may be configured to usecontrol signal coupling 2635 to block control signals generated bymanual user interface 2620 from reaching control signal interface 2671.More generally, controller 130 may be configured to use control signalcoupling 2635 to implement and/or supplement any of the methods and/ormethodologies described herein.

Embodiments of the present disclosure can use such techniques to provideadaptive, reliable, and accurate docking assist and/or other types ofnavigational control for mobile structures, for example, and can do sorelatively inexpensively by leveraging already-installed navigationcontrol systems and related cabling and control signal techniques, asdescribed herein.

In addition and to supplement the above, embodiments of docking assistsystem 2600 may be configured to provide a linearized response frompropulsion system 2670. For example, a typical internal combustionmarine engine use to turn a prop or otherwise generate thrust is oftenimplemented by a semi-continuously variable engine (in terms of RPM) anda gearbox providing discrete gear changes (e.g., typically Reverse,Neutral, Forward). Such implementation provides for semi-continuouscontrol from full-thrust in reverse, through neutral, to full thrustforwards, except that internal combustion engines for marineapplications typically operate at all times at or above a minimum idlespeed. For docking assist system 2600, this implies that propulsionsystem 2670 (e.g., when implemented with an internal combustion engine)can apply either no thrust (when in neutral) or at least a minimumthrust produced when propulsion system 2670 is idling in gear. Suchdiscontinuity of “minimum thrust” can present problems for navigationcontrol systems, such as when requiring just half of the minimum thrustto maintain position against the wind, or a third of the minimum thrustto slightly correct a course. In a position-hold scenario, withoutappropriate compensation, docking assist system 2600 would oscillateabout a set point, as a bit-too-much thrust is constantly applied andcorrected for with (again) a bit-too-much thrust. Embodiments provide aframework to modulate the thrust provided by propulsion system 2670 toapproximate continuous response through a discontinuous region overtime, without over-stressing elements of propulsion system 2670 (e.g. bycausing a transmission to come in and out of gear too often). Suchembodiments allow continuous control techniques to be applied limitedonly by the speed of associated gearboxes (e.g., an element ofnavigation control system 190 (e.g., other modules 180).

FIG. 33 illustrates a graph 3300 of an unmodulated propulsion systemthrust as a function of demand in accordance with an embodiment of thedisclosure. For example, graph 3300 may illustrate thrust output ofpropulsion system 2670 (e.g., propulsion system 170 and/or thrustmaneuver system 172) as a function of demand provided by userinterface/controller 120/130 and/or joystick 2620. In FIG. 33, graph3300 includes continuous demand responses 3310 and 3312 and neutralregion 3320 characterized by zero or neutral output thrust response 3314and the discontinuities at forward and reverse minimum output thrusts atpoints 3322 and 3324. The discontinuity is clearly visible at about±0.2, where there is no output thrust as the system passes below idleRPM (and drops into neutral), and where the thrust demand does notproduce values of output thrust smaller than ±0.2. Embodimentscompensate for this discontinuity by modulating between N and F/R stateswith a duty cycle calculated to result in an approximation of thedesired thrust when the desired thrust is below the idle or minimumthrust (here ±0.2), without risking damage to propulsion system 2670.Continuous demand responses 3310 and 3312 are shown in graph 3300 aslinear demand responses, but in other embodiments may be non-linear (butstill continuous through to a maximum RPM for propulsion system 2670).While the framework is described here in the context of control for amarine engine implemented propulsion system 2670, the framework isgenerally applicable to any actuator exhibiting both continuous anddiscrete response regions, similar to those shown in FIG. 33.

In general terms, embodiments designed to address these continuitiesproduce control signals that fulfil the following criteria: produce(over a relatively short time period) an approximate desired thrust; andminimize a cost function representative of mechanical strain onpropulsion system 2670 (e.g., minimizing the rate of gear changes). Forexample, docking assist system 2600 may be configured to determine adesired thrust demand magnitude is equal to or greater than a minimumthrust output for propulsion system 2670 and simply apply or passthrough the corresponding desired thrust demand to propulsion system2670. This operation may be referred to as adhering to the “continuitycriterion.” Docking assist system 2600 may also be configured todetermine the desired thrust demand magnitude is less than a minimumthrust output for propulsion system 2670 and to modulate the thrustdemand (and thereby, the output thrust) between zero thrust and theminimum thrust output by generating a thrust demand control signalimplemented by a waveform (e.g., in some embodiments similar to a squarewave) where the amplitude of the waveform corresponds to the minimumthrust output, the duty cycle of the waveform is set equal to thedesired thrust demand divided by the minimum output thrust of propulsionsystem 2670, and the frequency of the waveform is set to a maximumthrust modulation frequency such that neither the “on” dwell time or the“off” dwell time of the waveform is allowed to become less than a presetor predefined minimum mechanical or shift lag (e.g., the frequency ofthe waveform is dependent or based on the preset minimum mechanical orshift lag and the calculated duty cycle and/or the desired thrustdemand). In various embodiments, the minimum mechanical lag (e.g., aminimum mechanical safety lag) may be set to reduce or eliminate risk ofmechanical damage to propulsion system 2670 caused by an attempted toofrequent modulation of the thrust output of propulsion system 2670between a neutral or zero thrust output and a minimum thrust output.

FIG. 34 illustrates a flow diagram 3400 of control loops to providelinearized response from propulsion system 2670 in accordance with anembodiment of the disclosure. In particular, flow diagram 3400 includeswaveform duty cycle control loop 3410 configured to receive or accept adesired thrust demand (e.g., “Thrust In”) and a minimum thrust output(e.g., “Gearbox Thresh”) and provide a corresponding duty cycle 3412 asoutput, at least in part to waveform frequency control loop 3420, asshown. Waveform frequency control loop 3420 may be configured to receiveor accept a minimum mechanical lag (e.g., “MinGearTime”) and duty cycle3412, convert the minimum mechanical lag into a frequency (e.g., usinginversion block 3422), and then select a waveform frequency 3426 (e.g.,using min selection block 3424) corresponding to the maximum allowablefrequency for duty cycle 3412 that includes waveform dwell times greaterthan the minimum mechanical lag, as shown.

In various embodiments, flow diagram 3400 may result in a time domaintransfer function for desired thrust demands less than the minimumthrust demand for propulsion system 2670. FIG. 35 illustrates a graph3500 of such time domain transfer function representative of a modulatedpropulsion system thrust as a function of thrust demand in accordancewith an embodiment of the disclosure. In FIG. 35, graph 3500 includesdemand sweep 3510 progressing from a continuous region across modulationregion 3520 (e.g., corresponding to neutral region 3320 in FIG. 33) anddefined or characterized by the discontinuities at forward and reverseminimum output thrusts at points 3522 and 3524. When used withpropulsion system 2670 and the associated inertia and environmentalfriction associated with operation of propulsion system 2670, theresulting thrust output and motion is smoothed to roughly match anydesired thrust demand below the minimum thrust demand (e.g., and anyaccompanying desired motion or hover).

Embodiments may extend such framework to a two dimensional system (e.g.a joystick with forward/reverse/left/right configurations). Flow diagram3400 maybe modified to include two instances of the included controlloops (e.g., one each for forward/reverse and left/right), for example,or flow diagram 3400 may be modified to iteratively act on one then theother, or one or the other as needed when one is outside the neuralregion and one is within the neutral region, as described herein. Afurther extension to this technique is to limit the rate of changebetween the discrete and continuous operating modes, such that theminimum mechanical lag is respected. For example, upon reaching theneutral region (e.g., based on a decreasing desired thrust demand),docking assist system 2600 should wait at least one mechanical laginterval before proceeding with the thrust modulation (e.g., reengaginggears), even if such reengagement would be triggered by moving into acontinuous operating region.

In addition and to supplement the above, embodiments offer the followingimprovements. For example, controller 130 may be configured to receiverelatively high resolution image of a docking environment (e.g.,catways, etc.) and render a display view on a display of user interface120 allowing a user to select a docking position and/or orientation formobile structure 101. Perimeter ranging system 148 may be configured toprovide fast and accurate (e.g., low noise and low latency) measurementsof a position of mobile structure 101 relative to a target location, forexample, and/or a relative velocity between mobile structure 101 and adock or other navigation hazard or waypoint.

In general, docking assist system 100 may be configured to identify andavoid navigational hazards, while ignoring objects that do not present anavigational hazard. As such, embodiments may be implemented withartificial intelligence (AI) systems and techniques differentiateobjects like sea gulls or floating debris that do not present anavigational hazard (indeed trying to avoid them would be dangerous)from, for example, the corner of a kayak, which could be of a similarsize and color but should be avoided. Such intelligentsystems/techniques may help determine a target pathway from a currentposition to a target location, avoiding obstacles, and taking intoaccount the geometry and safety zone corresponding to mobile structure101.

In various embodiments, docking assist system 100 may be configured todetermine a difference between a target pathway and the actual position,the corresponding position and heading errors, and account for relatedsideslip dynamics. For example, such errors may be used to generatecompensating navigation control signals. Because different boats operateaccording to different characteristic dynamics, embodiments provide suchcompensation adaptively. For example, often control signals need to beconverted into the thrust axes of a particular vessel: some vessels haveside thrusters, some have twin screws, some have thrust maneuversystems.

Marine vessels can be complex places to install perimeter rangingsystems. Installation is often done by end users on old boats, or bydealers. Unlike automotive applications, marine installations are oftennot factory fit. As such, installation and composition of elements ofperimeter ranging system 148 should emphasize: low-latency; de-warping,stitching and motion stabilization of the sensors, with minimal cablingcoming down to the control point; architecture that can accommodate arange of vessel sizes (e.g., 10 ft to 100 ft), and from sail to power;provide imagery into the distance with good resolution when approachinga dock (e.g., at 20 m), and to see all round as well as down fordocking; provide imagery for a plan view of the environment so obstaclescan be avoided and docking can be safe in all situations; minimalinstallation and setup, minimum number of sensors/installation points;small form factor and lightweight for ease of installation high up (>3 mheight); self-aligning, or with integral levelling (bubble level).

In some embodiments, docking assist system 100 may be configured togenerate an audible warning to alert a user as the vessel's virtualbumper zone approaches an obstacle. The tone or volume can be modulatedto indicate proximity. Furthermore, the region of proximity can behighlighted on a synthetic elevated view overlay, for example thelineation line between water and dock/boat can be overlaid on top of thesynthetic elevated view and the proximity ‘hot spots’ can be pulsing inintensity.

For assisted docking, this visible warning can be useful in explainingto the user why the system is attenuating demand. For example, if thesystem has picked up a floating fender which the user would typicallyignore but the system counts as an obstruction, then the pulsatingoutline around the floating fender would explain to the user why thejoystick demand for velocity is not being delivered.

Should the virtual bumpers prevent entry into a tight berth, dockingassist system 100 may notify the user and provide options. One is toreduce the size of the virtual bumper region, but this can be onerousand take time to do safely. Another is to allow the user to override thevirtual bumpers via an override button, a user joystick action such asapplying full joystick (like a kick-down switch on cruise control in acar), or other user interface techniques.

Blind spots can present a safety problem, over the sides, and aft, butparticularly over the bow of a vessel. As the vessel moves forwards andapproaches a dock, the dock can become obscured. To combat this, dockingassist system 100 may in some embodiments include a camera or a pair ofcameras looking over the bow and mounted on the toe rail or guard rail.In other embodiments, docking assist system 100 may be configured to useprior imagery of the dock, when it was visible, along with translationalmotion measurements (which themselves can be inferred from changes inimagery over time), to infer a range to the occluded dock edge. A camerasystem has the advantage over a human operator that, by using visualodometery (e.g., a measure of translational motion using differences inimages over time), the historical imagery can be slid into exactly theright place relative to the boundary of the vessel. The existence ofsuch blind spots can be automatically detected and sized during acalibration phase where the vessel performs a 360° spin, such as justafter the system is installed.

A risk for autonomous docking is that the system drives the boat into anobstacle, either because an obstacle has not been detected, or becauseof a system fault. An “attenuation principle” can be applied tooperation of docking assist system 100 to eliminate the risk of system100 driving mobile structure 101 into an obstacle. This principle isdefined such that detection of an obstacle cannot lead to velocitydemand, but instead leads to the attenuation of a user's joystick orother manual user interface input, for example, or an attenuation ofsome other source of velocity demand (e.g., a docking assist navigationcontrol signal/demand). For example, the output of the perimeter rangingsystem 148 can include a signal (or set of signals, forwards sidewaysrotation) in the range 0→1 where 1 implies leave the users velocitydemand intact, and 0 means apply zero velocity demand (brakes)regardless of the user's demand. Such an attenuation signal cannot causea vessel crash, but it can frustrate the user by preventing velocitydemand, and it can fail to prevent a user induced crash. In variousembodiments, the attenuation signal/gain adjustment is only allowed tofall below 1 where the user demands velocity towards an obstacle.Velocity demand away from an obstacle will never cause attenuation.Sliding along an obstacle is therefore possible, for example if a vesselis sliding into a dock, and the virtual bumper is close to touching downone side, then sideways velocity demand may be attenuated to 0 whereasforwards velocity demand would not be restricted until the bowapproaches the front virtual bumper, so the vessel may continuefollowing the path of least resistance along the direction of the dock.

In some embodiments, docking assist system 100 may be configured togenerate a synthetic elevated view derived from a fixed camerainstallation, as described herein, or from an unmanned aerial vehicle(UAV) which can be automatically deployed and controlled by dockingassist system 100. In some embodiments, as a user modifies the center orangle of a synthetic elevated view on the touch screen, docking assistsystem 100 may communicate with the UAV to cause it to move accordingly.

For boats with conventional propulsion systems (e.g., rudder and motor),it is not always possible to stop the boat (the wind will take the boatas the rudder loses control). In this case, the maneuver can bedescribed as dynamic, which means it must be done in one go, keepingboat speed up. The stronger the wind and current, the higher the minimumboat speed. For these maneuvers, assisted docking may not be possible,and autonomous docking may be required. Once the user has specified thetarget location, docking assist system 100 determines a pathway which isappropriate for the vessel type. For example, a sailboat can come to adock at 45°, then turn at the last minute and go into reverse to slowdown. An outboard steered power boat cannot be docked using thisstrategy; rather, the engines should be turned to opposite lock andreverse thrust applied at the last minute, slowing the vessel andtucking in the stern. Vessels with bow thrusters have docking patternswhich are different again. The boat type may be selected as part ofcalibration of docking assist system 100, and the appropriate set ofdocking patterns is then made available for selection by the user. For adocking scenario, docking assist system 100 may pick from the list ofpossible patterns and fit the chosen patterns to the specific scenario.A user may then be offered a set of choices (overlaid on a display ofuser interface 120) and can select their desired choice.

For velocity control, it is important to have a good measurement ofvelocity over the ground. GPS may sometimes not be good enough due torandom walk (unless differential GPS is used, but this requires a basestation mounted to the dock, with a radio link to the rover onboard),and noise in Doppler can be a limiting factor. So another technique isneeded, and a generic velocity measurement system should be capable ofdeployment anywhere worldwide. Docking assist system 100 may beconfigured to use visual odometry derived from imagery provided byvisible or thermal, mono or stereo cameras. For single camera odometry,scaling is required, and one scaling solution is to scale from GPS athigh speeds (>2 kts) where GPS suffers less from random walk.

In some embodiments, docking assist system 100 may be configured tocompensate for wind and current effects by explicitly estimating theeffects of wind and current through modelling. The wind can be measuredthrough a wind vane and the current estimated from the differencebetween water speed measurements (e.g., a two-axis electromagnetic log,for example, which can measure water velocity as a vector) and groundspeed, which can be measured using visual odometry employing embodimentsof perimeter ranging system 148. Once current and wind are known, modelscan be applied to determine the effect on the vessel (e.g., wind tendsto blow the bow downwind, due to the asymmetry where wind pressure actsat 0.25 of the chord of a body, which is ahead of the center of mass andahead of the center of lateral resistance of the hull in the water). Theexpected disturbance can be used to determine a counteracting thrustdemand set, as a feedforward term in the controller, reducing the demandon the feedback terms and improving overall control.

Boats vary in mass, thrust, and control dynamics (e.g., delays in gearchanging, pod rotation and throttle changes, and dead zones which maysurround the neutral joystick position). One way to handle thesevariations is a robust control system, as described herein. Furthermore,the dynamics may be measured through observation during vessel use(either manually by the user, or automatically).

In various embodiments, docking assist system 100 may be configured touse video analytics to highlight navigational hazards such as objects(like posts) which might otherwise go unnoticed or are within a certaindistance of a known route. Once docking assist system 100 hasestablished the pathway and yaw angles of a docking route, this may bedisplayed to the user as a zone through which the vessel occupies space,such as an animated walkthrough of the route/yaw the vessel will take,or other methods to show a user the expected route context before theuser accepts the docking maneuver.

In the automotive space there are hybrid control systems, such as wherea user controls brakes, throttle, and clutch, but the steering angle isautomated or assisted. The same can be applied to the marine space,where the rudders, throttles, and gear positions, for example, can becontrolled by the skipper or docking assist system 100. However, unlikeautomotive where speed and steering are independent variables,watercraft have considerable cross coupling. One form of hybrid controltechnique which is more suitable to boating systems is for the maneuverto be controlled automatically, but the pace of the maneuver to becontrolled or adjusted by the user. For example, once a maneuver isselected, a joystick's right/left/rear/twist directions could beignored, and the forward/neutral joystick dimension could be used toindicate to the system whether to run the maneuver at full speed, or toslow or halt the maneuver, depending on the forward deflection of thejoystick.

In embodiments where system 100 includes a joystick or other manualinterface device, docking assist system 100 may be configured toautomatically activate assisted docking whenever the joystick/manualuser interface is in use (whether or not synthetic elevated view camerais being viewed), to automatically open pre-defined applications on oneor more user interfaces whenever the joystick/manual user interface isin use, and/or to automatically enable assisted docking whenever asynthetic elevated view is displayed. In embodiments where system 100does not include a joystick or other similar manual interface device,docking assist system 100 may be configured to enable assisted dockingwhen throttle control drops below a defined threshold; speed-over-grounddrops below a defined threshold. In one embodiment, object recognition(e.g., using AI systems and techniques) may be used to identify andplace mobile structure 101 dead-center over a trailer as a user drivesforwards.

When completing an assisted docking maneuver, a docking or navigationassist or autonomous system should be able to not only “see” the worldthrough sensors but also understand enough about the relationshipbetween the vessel and the world to make informed decisions about whatmaneuvers are safe. A typical spatial mapping solution (such as thatused by assisted docking) can provide an occupancy map (e.g., a rasterrepresentation of where navigation hazards and/or other objects are inthe world) but no real understanding of what the occupancy map meanswith respect to maneuvering. Humans are used to intuiting based onspatial awareness, but for computer vision, developing spatial ormaneuvering intuition can be difficult. Such “semantic analysis” isoften very computationally expensive (due to the amount of data thatmust be processed) and/or use machine-learning algorithms (which aretypically very computationally expensive, difficult to produce, and verydifficult to prove that they will work reliably in all scenarios). Bothissues increase cost and reduce robustness.

Embodiments described herein are capable of taking the occupancy map(e.g., raster representation) and producing the semantic understandingrequired to inform a docking system of the environmental surroundings ina very computationally efficient way. For example, embodiments areanalytical rather than based on machine learning or probabilistictechniques, so they are repeatable, robust, and predictable. Becausethey are computationally efficient, they can be performed usingrelatively inexpensive hardware and do not need to rely on, for example,a GPU.

For example, some embodiments may be implemented as a scene analysispipeline, such as scene analysis pipeline 3600 shown in FIGS. 36A-B,which may be configured to receive an idealized mobile structureperimeter 3610 (e.g., a two dimensional planar figure or vessel polygonformed of a number or set of connected line segments and representingthe extents of the perimeter of the mobile structure), a virtual bumperthickness 2612 (e.g., defining a spatial safety buffer about the mobilestructure perimeter), an occupancy map 3614 (e.g., a selection ofpositions of detected objects or portions of objects in the environmentabout the mobile structure), and a (raw) velocity demand 3616 (e.g.,docking assist parameters), for example, and provide a variety ofsemantic data (e.g., distances to incursions 3620, 3624, user interfacerenderings and/or associated imagery and/or diagnostic data 3622, 3624,3632 to provide feedback to a user) and navigation controls signals(e.g., limited velocity demand 3630, which may include at least onevelocity component that is reduced in magnitude and/or reversed indirection relative to a corresponding velocity component of the rawvelocity demand, as described herein) to safely maneuver or assist inmaneuvering the mobile structure. In various embodiments, scene analysispipeline 3600 may be implemented by and/or segregated into a sceneanalysis publisher 3640 and a velocity limiter 3650, as shown in FIGS.36A-B. In addition, controller 130, user interface 120, and/or otherlogic devices and/or elements of system 100 may be configured to performand/or otherwise implement each function, block, and/or element of sceneanalysis pipeline 3600, as described herein.

The goal of scene analysis pipeline 3600 is to take a rasterrepresentation of the world (such as a binary occupancy map or grid3614) and user velocity demand 3616 (e.g., linear (X/Y) and yaw ratedemand (Z)) and compute the velocity most-similar to the velocity demandinput that can be safely executed. Scene analysis pipeline 3600 may alsobe configured to return a metasegment state 3624, which is the distancefrom a segment of the vessel polygon 3610 to the nearest obstacle alongthe normal of any part of the continuous or contained vessel polygon(which can be used for a visual indication via renderings by userinterface 120 of how close various parts of the vessel are to apotential collision, hereon referred to as a bumper incursion, which maybe represented by differently colored segments/metasegments of vesselpolygon 3610 as rendered within a docking assist user interface displayview and/or any other display views, as described herein). Vesselpolygon 3610 may be expressed as a set of XY points, representing thewidest point of the vessel (essentially the “plan view” of the mobilestructure). Bumper thickness 3612 is a real number that corresponds to a“safety zone” (in assisted docking parlance, virtual bumper) size, whichis a selected or regulatory minimum distance to keep between the vesseland any navigation obstacle. Occupancy map 3614 (e.g., the “world”) maybe expressed as a set of points (e.g., relative positions) in polar formcorresponding to at least one object detected within perimeter sensordata provided by perimeter ranging system 148, each representing theclosest point (e.g., a closest approach distance of the at least oneobject) relative to the center of navigation (e.g., center of thevessel) in a particular selected azimuth range (e.g., 0-360 degrees orsome subset thereof): if all the nearest world points/positions in anazimuth range can be avoided, it follows that all other world points inthat azimuth range will also be avoided.

For example, FIG. 37 shows a scene analysis map 3700 (e.g., a displayview rendered via user interface 120) including an embodiment ofidealized mobile structure perimeter 3610, occupancy map 3614, and anintervening virtual bumper corresponding to virtual bumper thickness3612, which may be used by navigation scene analysis pipeline 3600 forautonomous and/or assisted navigational control for a mobile structurein accordance with an embodiment of the disclosure. As shown in FIG. 37,scene analysis map 3700 includes world points/positions 3714 and worldsegments 3715 corresponding to occupancy map 3614, mobile structureperimeter 3710 and virtual bumper perimeter 3712 (e.g., which may eachalso be implemented as a combination of perimeter points and segments),and map origin 3701, which may correspond to the center of mass/rotationof the vessel linked to mobile structure perimeter 3710. The followingelements may be determined by scene analysis pipeline 3600 to be used aspart of the velocity limit solution.

For world points/positions that are outside virtual bumper perimeter3712 (as shown in scene analysis map 3700 of FIG. 37):

-   -   (A) The shortest distance between virtual bumper perimeter 3712        (or mobile structure perimeter 3710) and the world in the fore,        aft, port, and starboard directions, determined as the shortest        of:        -   (1) the fore (line 3720), aft (line 3721), port (line 3722),            and starboard (line 3723) perpendicular distances from the            nearest virtual bumper perimeter point to the nearest world            segment; or        -   (2) the fore, aft, port, and starboard perpendicular            distances from the nearest world point to the nearest            virtual bumper perimeter segment (alternatively represented            by lines 3720-22 and 3724).    -   (B) The shortest angle that the vessel could turn through in        both port (arc 3723)/starboard (arc 3725) directions before        either a world point intersects with virtual bumper perimeter        3712 or a virtual bumper perimeter point intersects with a world        segment.

For world points/positions that are incurring (e.g., inside virtualbumper perimeter 3712, as shown in scene analysis map/display view 3800of FIG. 38):

-   -   (A) The perpendicular distance between incursion point 3820 and        the nearest virtual bumper perimeter segment.    -   (B) The angle at which incursion point 3820 is incurring        relative to the nearest mobile structure perimeter segment        and/or virtual bumper perimeter segment.    -   (C) The X/Y position of incursion point 3820 relative to the        nearest mobile structure perimeter segment and/or virtual bumper        perimeter segment.

In various embodiments, scene analysis publisher 3618 may be configuredto receive raw world data, such as a polar form occupancy map 3614 asdescribed herein, and an idealized vessel shape in the form of a twodimensional polygon, such as mobile structure perimeter 3610, orientedrelative to occupancy map 3614 so as to substantially represent the realworld navigation status the mobile structure represented by mobilestructure perimeter 3610. Scene analysis publisher 3618 may include abumper detector 3641 that receives mobile structure perimeter 3610 andgenerates: a list or set of world segments that are drawn between allpairs of world points/positions that are fully outside of virtual bumperperimeter 3712; a list of world points/positions that are inside ofvirtual bumper perimeter 3712; and a list of distances from all worldpoints/positions (within a certain distance of interest) to the vessel,to feed metasegment state composition 3642. Linear/radial detectors3643, 3644 are passed a locus based on mobile structure perimeter 3610and virtual bumper thickness 3612 (e.g., generated by pseudolocusgenerator 3645), and may be configured to use this in conjunction withthe list of world segments from outside of the bumper to determine: howfar the vessel can move fore, aft, to port, and to starboard before acollision or incursion occurs; and how far the vessel can rotate in aport or starboard direction before a collision or incursion occurs. Theoutputs of detectors 3643, 3644 are composited by block 3646 into acollision solution (message) 3620, which may be passed to velocitylimiter 3650.

Linear detector 3642 may be configured to measure the distance to firstincursion in a straight line along a given vector. Four linear detectorinstances may be used to measure the port, starboard, bow and sterndistances. Two directions of incursion are defined:vessel-projection—For each perimeter point, what is the first/closestincursion with a world segment?; world-projection—For each world pointor position, what is the first/closest incursion with a perimetersegment? These two methods of projection permit arbitrarily sparsevessel/world representations while retaining reliable collisiondetection by setting the incursion distance to the minimum of thedistances determined according to the two directions (e.g., for eachsegment/metsegment/point of mobile structure perimeter 3610 and/orvirtual bumper perimeter 3612. For example, if a vessel or bumperperimeter were represented as a sparse-enough polygon and a denselyspecified world contained a single point representing an obstacle, it isfeasible that the perimeter points may not intersect with the worldsegments, as shown in scene analysis map 3900 of FIG. 39. As shown inFIG. 39, vessel-projection 3920 correctly determines the minimum lineardistance to world segment 3715, while vessel-projection 3921 incorrectlydetermines the minimum liner distance to world segment 3915 (e.g.,correctly identified along world-projection 3922). Embodiments can testfor this by deliberately under-representing the world, such thatvessel-projection or world-projection is necessary to find all potentialcollisions.

A pseudocode embodiment of a high-level process for linear detector 3642is as follows:

 define projectionVector // A 2D line defining the direction andmagnitude of the linear  ″lookahead″, e.g. {10,0} for a 10m forwardssearch range  for (LineSegment boatSegment in boatSegments)   for(LineSegment worldSegment in worldSegments)    intersection =testForIntersection(worldSegment.startPoint, worldSegment.startPoint -projectionVector, boatSegment)    if (intersection.doesIntersect)    closestIntersection = min(closestIntersection,intersection.intersectionDistance)    intersection =testForIntersection(boatSegment.startPoint, boatSegment.startPoint +projectionVector, worldSegment)    if (intersection.doesIntersect)    closestIntersection = min(closestIntersection,intersection.intersectionDistance)  return closestIntersection

There also exists a concept of “back-projection,” which is a rudimentarymechanism for handling world points inside virtual bumper perimeter3712. As shown in scene analysis map 4000 of FIG. 40, incurring point4015 might not be handled correctly, as it is not in front of thevessel, so it might not be detected if the scene analysis just projectedforward. Back-projection starts looking from behind the vessel and scansforwards. In alternative embodiments, a virtual bumper detector isrelied upon to detect any world points projected as inside virtualbumper perimeter 3712 and/or mobile structure perimeter 3710. If sceneanalysis does detect any points projected as inside a perimeter, it mayproject them as negative distances. Embodiments catch any world pointsthat are projected within the perimeters due to some failure of thevirtual bumper detector causing world points to be projected inside theperimeters.

More generally, controller 130 and/or user interface 120 may beconfigured to generate a set of world segments corresponding to and/orlinking world positions within a received occupation map, determine alinear vessel projection incursion distance for each perimeter point ofa virtual bumper perimeter corresponding to a received mobile structureperimeter based, at least in part, on the generated set of worldsegments, and determine a linear world projection incursion distance foreach world position of the received occupation map based, at least inpart, on the virtual bumper perimeter. The minimum of the determinedlinear vessel projection incursion distances and the determined linearworld projection incursion distances may then be passed to velocitylimiter 3650 to limit a raw velocity demand, as described herein.

Radial detector 3644 may be implemented similar to linear detector 3643,though it detects potential collisions if the vessel were to turn aboutorigin/center of mass 3701 instead of move linearly. In variousembodiments, a single radial collision detector 3644 can produce thesolution for turning to both port and starboard in one calculation, sothere is only need for one instance of radial detector 3644. The conceptof vessel-projection and world-projection also exists in the radialdetector, for the same reasons and with the same implications.Vessel-projection is considered an extra, relative to world projection,which is the projection in the standard ROS coordinate system. As such,vessel-projection is achieved using a reverse flag in _projectAndUpdateand there is no need for back-projection. More generally, controller 130and/or user interface 120 may be configured to generate a set of worldsegments corresponding to and/or linking world positions within areceived occupation map, determine a radial vessel projection incursiondistance for each perimeter point of a virtual bumper perimetercorresponding to a received mobile structure perimeter based, at leastin part, on the generated set of world segments, and determine a radialworld projection incursion distance for each world position of thereceived occupation map based, at least in part, on the virtual bumperperimeter. The minimum of the determined radial vessel projectionincursion distances and the determined radial world projection incursiondistances may then be passed to velocity limiter 3650 to limit a rawvelocity demand, as described herein.

Bumper detector 3641 may be configured to receive a set of world pointsand determine which are inside virtual bumper perimeter 3712, and by howmuch. Specifically, bumper detector 3641 may be configured to output thedistance into virtual bumper perimeter 3712 for any segment that a worldpoint has crossed over (rho), and the world-relative angle of theincursion vector (theta). Bumper detector 3641 may be capable of sortingpoints into inside/outside virtual bumper perimeter 3712 for a range ofdifferent bumper sizes simultaneously, as required for generating alertsegments. To facilitate this, bumper detector 3641 manages its ownbumper locus, independently of the other detectors. Bumper detector 3641may be initialized with a “max scanning distance”, which it uses tocreate a locus that is big enough to cover any requested bumper/scanningregion size (e.g. for a 1 m bumper and 10 m alert-segment region). Apseudocode embodiment of a high-level process for bumper detector 3641is as follows:

 define requestedRanges // All ranges of interest (for example a bumpersize and an alert triggering distance)  define maxScanningDistance //largest of requestedRanges  define segmentStartWorstCaseDistanceToBoat// track the worst-case distance to the boat for the start of a segment define segmentEndWorstCaseDistanceToBoat // track the worst-casedistance to the boat for the end of a segment  define worldSegments //The list of segments that comes in from joining up all the points  //The outer loop iterates per world segment  for (LineSegment worldSegmentin worldSegments)  // Segment is guaranteed continuous if this is notthe first segment and the previous segment end matches the start of thissegment   segmentIsGuaranteedContinuous = isNotFirstSegment &&worldSegment.startPoint == lastWorldSegment.endPoint  // The world comesin as a list of (potentially) discontinuous segments. Typically,segments will be continuous and form a polygon (although there areexceptions to this). This means that in the majority of cases, it can beassumed that the end point of one segment is equal to the next one, andas such that point does not have to processed twice.  // The process isabout to start checking this particular world segment, so initialize the″worst case distances″ appropriately   if(segmentIsGuaranteedContinuous)  // Process can copy the result from theend of the previous segment (as it's the same point)   segmentStartWorstCaseDistanceToBoat =segmentEndWorstCaseDistanceToBoat   else  // Can't guarantee that thestart of this segment == the end of the previous segment, so do not   segmentStartWorstCaseDistanceToBoat = Inf  segmentEndWorstCaseDistanceToBoat = Inf   for (LineSegment boatSegmentin boatSegments)    if (!segmentIsGuaranteedContinuous)    startPointIncursion = getIncursion(boatSegment,worldSegment.startPoint);    endPointIncursion =getIncursion(boatSegment, worldSegment.endPoint);    for (RangethisRange in requestedRanges)     if (startPointIncursion.isIncurring)     thisRange.addIncurringPoint(worldSegment.startPoint)     segmentStartWorstCaseDistanceToBoat = min(segmentStartWorstCaseDistanceToBoat, startPointIncursion.distanceToBoat)     if(endPointIncursion.isIncurring)     thisRange.addIncurringPoint(worldSegment.endPoint)     segmentEndWorstCaseDistanceToBoat =min(segmentEndWorstCaseDistanceToBoat,startPointIncursion.distanceToBoat)   for (Range thisRange inrequestedRanges)    if (segmentStartWorstCaseDistanceToBoat >thisRange.distance && segmentEndWorstCaseDistanceToBoat >thisRange.distance)  // This world segment is clearly well outside thebumper at the requested range, as neither end of the segment isincurring     thisRange.addSegmentOutsideOfRange(worldSegment)

A locus is defined by the set of all points with locations satisfyingspecific conditions. For example, to generate virtual bumper perimeter3712, the condition may be a fixed distance from mobile structureperimeter 3710, such that the locus of a square would be a square withrounded corners. As sued herein, virtual bumper perimeter 3712 may bedefined as the locus of mobile structure perimeter 3710, with the fixeddistance being the bumper size. A locus is a function containinginfinitely many points, typically it is approximated by a pseudolocus.As such, pseudolocus generator 3645 may be configured to receive mobilestructure perimeter 3710 and generate virtual bumper perimeter 3712 as apseudolocus implemented by a dense polygon that is sufficient for sceneanalysis, as described herein. For example, as shown in scene analysismap 4100 of FIG. 41, virtual bumper perimeter 3712 is implemented as apseudolocus with a series of line segments 4112 approximating acontinuous curve locus about vessel perimeter point 4110 of mobilestructure perimeter 3710. A pseudocode embodiment of a high-levelprocess for pseudolocus generator 3645 is as follows:

 define LocusPolygon  define SourcePolygon // Polygon of the boatoutline  define BumperSize // Size of bumper  define maxError // Maximumpermissible approximation error (meters, or whatever XY are in)  for(LineSegment thisSegment in SourcePolygon)  // Add straight-line segmentparallel to incoming segment (offset by bumperSize)  LocusPolygon.addSegment(thisSegment + (thisSegment.normal *bumperSize))  // Add segments to go around the corner. Get maximum anglethat can be approximated by a single segment (derived from chordgeometry)   maxAngleForSingleSegment = acos((distance - maxError) /distance)*2  // Get required number of split segments (has to be wholenumber no smaller than angleToCover/maxAngleForSingle Segment)  nRequiredSteps = ceil(abs(angleToCover / maxAngleForSingleSegment)) // Add actual steps around the corner   for (int i = 0; i <nRequiredSteps, i++)   LocusPolygon.addSegment(SegmentRequiredForASmallAngularSection)  Ingeneral, a polygon can be split into a number of metasegments, which canbe segments of equal length that split the perimeter of the polygon intoequal parts, regardless of the position of the vertices of the polygon(i.e. a metasegment need not start/end on a vertex). A pseudocodeembodiment of a high-level process for metasegment state composition3642 is as follows:  define perimiterLength // Sum of length of alledges of the polygon  define nMetaSegments // The desired number ofmetasegments  define currentMetasegment = 0  metasegmentLength =perimeterLength / nMetaSegments  for (LineSegment thisSegment inpolygonSegments)   metasegmentEndPoint = metasegmentLength *(currentMetasegment + 1)   if (thisSegment.end > metasegmentEndPoint)   {Split the segment, assigning the metasegment ID of the first part ascurrentMetasegment and the second part's metasegment ID as the nextmetasegment}    currentMetasegment++

In practice, the number of actual metasegments is double the requestedquantity, such that the following numbering scheme can be used tofacilitate centering segments about the origin point of a polygon:Underlying metasegment ID: 1 2 3 4 5 6 7 8; Reported metasegment ID: 1 22 3 3 4 4 1. Each metasegment state may then be reported as theworst-case bumper incursion of any underlying boat segment with thatmetasegment ID. For example, if three boat segments have the metasegmentID of 1, then the metasegment distance of metasegment 1 is the closestdistance to an obstacle of any of these three segments.

FIGS. 42A-B illustrate a software architecture 4200 to providenavigation scene analysis for autonomous and/or assisted navigationalcontrol for a mobile structure in accordance with an embodiment of thedisclosure. In embodiment shown in FIGS. 42A-B, software architecture4200 implements aspects of scene analysis pipeline 3600 of FIG. 36A-B,including linear detector 3643, radial detector 3644, bumper detector3641, and scene analysis publisher 3640 (shown segregated into sceneanalysis publisher 3640-1 and 3640-2). In some embodiments, softwarearchitecture 4200 may include CollisionDetector block 4202,SpatiaIDataConsumer block 4204, and/or IRangeSink block 4206, as shown.In various embodiments, each detector optionally has an associated*Derivations object, which is populated based on either incoming vesselor world data, depending on the needs of the detector. This facilitatescaching any derived data such that they only need to be processed whendata arrives. For example, some of the collision calculations onlyupdate when the vessel perimeter is updated, which is stored in aderivations cache to save doing the entire calculation every time newworld data comes in. It also handles the rare scenario where new worlddata has not arrived, but a new collision solution is required due tothe reception of a new vessel perimeter.

In the embodiment shown in FIGS. 42A-B, Vector2 provides two dimensionalfunctionality while maintaining functionality with three dimensionaldata structures, for example, and can store an XY point. PointList is anordered set of points, with extra defined functionality (e.g.,monotonicity and sorting functions). The points bear no relation to eachother and are a subclass of std::vector<Vector2>. LineSegment is awrapper for a pair of Vector2 objects. It caches the difference betweenthe two vectors (dx and dy), and the determinant of the line segment. Itprovides for translating the segment by a Vector2 (and updating thedeterminant accordingly), and also provides some printing/equalitychecks. ILineSegmentList provides a read-only vector-like interface to alist of line segments, which is motivated by the need to create aread-only interface in order to force the line segments contained toadhere to particular geometric rules. ILineSegmentList does allowclear/reserve but these may be overridden by the base class.ILineSegmentList::DiscontinuousLineSegmentList adds write access to theLineSegmentList with no checking for point continuity or any otherrules. Put differently, it behaves even more like a vector of unrelatedLineSegment objects. LineSegmentList::Polygon creates a list ofLineSegment objects from a list of points (be it a range set, apointlist or a list of XML points). It defines each Line Segment as“joining the dots” between every point in a set of provided points. Itdoes not allow modification, so continuity is preserved. This allows anyconsumers of a polygon to safely assume that the end of each linesegment will be equal to the start of the next one. It may also containthe pseudolocus and metasegment logic.

Velocity limiter 3650 of FIG. 36B may be implemented according to avelocity limiting framework designed so that a minimum velocity can beinduced, as well as a maximum velocity limited (to facilitate pushbacketc.), as described herein. The limit may be created in two passes; anyvelocity modification caused by the incurring points is imparted on thevelocity demand first, then the perpendicular bumper limiting is appliedto the resultant velocity. Specifically:

The XYZ velocity limit imposed by each incurring point based on itslocation is applied to the velocity limit in turn. Using the position ofthe point relative to the center of navigation, the 2D velocity vectorthat the point would travel through if the full velocity demand wereapplied to the center of navigation is calculated. For example, in FIG.38, turning to port (with no linear motion) would cause incursion point3820 to move directly away from virtual bumper perimeter 3712, soincursion point 3820 would have a mostly negative Y velocity and mostlyconstant X (at least initially). If the vessel was to have a purelylinear (translational) velocity demand, the velocity of incursion point3820 would equal the opposite of that demand (for example if the vesselmoved forwards at 1 m/s, incursion point 3820 would move in the oppositedirection at 1 m/s. If the vessel were to move to starboard whileturning to port, the point would stay approximately still relative tothe vessel, as the stern moves to starboard but the bow remainsrelatively static,

A rho reduction factor may be calculated based on a set of rules aroundthe expected velocity of the world point. The velocity demand may thenbe scaled by the rho reduction factor (in X, Y and yaw in equalamounts). If the expected velocity of the point would cause bumperincursion to increase, the rho reduction factor for this point may beset to 0. If it is due to move the point away from the bumper, the rhoreduction factor may be set to 1. This functionality generates portions3726, 3727, 3728 of FIG. 37 and portion 3826 of FIG. 38, whichcorresponds to the rho reduction factor for all possible X/Y velocitydemands for the current yaw demand.

Once the various rho reduction factors are determined, the smallest rhoreduction factor from the set of incurring points may then be applied tothe velocity demand. In some embodiments, the rho reduction factor maybe limited to 0 or 1, which means that the velocity demand could be “on”or “off.” In other embodiments, there can be a progressive rho reductionfactor for velocity demands that would limit the velocity of the pointperpendicular to the boat, proportional to the closeness of the point tothe boat polygon, for example, or according to a different metric.

The reduced velocity demand then goes through perpendicular bumperlimiting, as described herein, where X, Y, and yaw velocities arelimited as a linear combination of current velocity in that direction,and distance to first incursion. Specifically, in some embodiments,velocity demand for a given axis=min(velocityDemand,currentVelocity*velocityLimitGain−currentDistance*distanceLimitGain) (inpseudocode).

The various diagnostics shown in FIGS. 36A-B may be generated in asimilar fashion. For example, portions 3726, 3727, 3728 of FIG. 37 andportion 3826 of FIG. 38 may be embedded within rviz to represent the rhoreduction factor imposed by each corresponding incurring point and/orclosest world point, as shown. The shapes in the center may representthe transfer function between an input raw velocity demand and theresulting output limited velocity demand. In some embodiments, FIGS.36A-B may include diagnostic rings and/or a grid, where each ring mayrepresent 10% of the available velocity demand range, and where eachgrid square may represent 1 m/s of velocity demand. Green/red dots maybe superimposed on the velocity limit rings to represent anddifferentiated the limited velocity demand and the raw velocity demand.

The velocity limiter architecture is designed with the ability to applya minimum as well as a maximum velocity, allowing the system to takesome active intervention if necessary. Embodiments may determine ajoystickRhoLimitScale, which may be used to linearly scale the joystickdemand based on whether a maneuver is safe or not (e.g., would itincrease bumper incursion?). In some embodiments, such factor may be setto either 0.0 or 1.0, while in others, it may be set to any valuebetween 0 and 1, inclusive. Pseudocode for binary functionality may beimplemented as follows (for each velocity component):

joystickRhoLimitScale = isThisManeuvreBad(VelRaw) VelSafe = VelRaw *joystickRhoLimitScale

If an obstacle is within virtual bumper perimeter 3712 for any reason(for example, through imperfect disturbance rejection, or throughincreasing the bumper size to encompass new obstacles), the velocitycontroller may be configured to actively push the vessel gently awayfrom the obstacle, upon detection. In some embodiments, thisfunctionality may be integrated with velocity limiter 3650. For example,instead of just setting an upper limit on velocity vectors that wouldcause world points to incur further, the system may be configured toapply a velocity vector as a function of incursion magnitude, in thedirection of incursion, to counteract the incursion. FIG. 43 illustratespushback thrust vector scenarios 4302, 4304, 4306 based on navigationscene analysis for autonomous and/or assisted navigational control for amobile structure in accordance with an embodiment of the disclosure. Forexample, prior to applying the maximum velocity (to prevent actions thatwould cause further bumper perimeter incursion), the system could beconfigured to sum all incursion vectors and use that resultant vector asa “base” velocity that can be added to or combined with the joystickdemand prior to bumper/linear/radial limiting (e.g., to overridecountermanding velocity demand). This would have the added benefit thatpushback from one obstacle would not push into another, as theirpushback vectors would automatically cancel out. Pseudocode for suchfunctionality is provided as follows:

VelPush = sum(bumperIncursion * pushbackSpeed) VelIdeal = VelRaw +VelPush joystickRhoLimitScale = isThisManeuvreBad(VelIdeal) VelSafe =VelIdeal * joystickRhoLimitScale {or a variation that prevents thevessel from getting trapped}

In some embodiments, the system may be configured to turn the vesseltowards an obstacle while moving away from the obstacle, for exampleeffectively having net-zero velocity on the bow and non-zero velocity onthe stern, so as to facilitate some docking or parking maneuversinvolving substantially pivoting about the bow to enter or exit a slip.In one embodiment, the system may be configured to do so by building aconvex hull of potential safe velocity actions given any detectedincursions and determining the nearest point inside that hull to arequested velocity demand. In related embodiments, the system may beconfigured to implement “sticky” virtual bumpers (e.g., stopping theboat from moving perpendicular to an object if it is too close,simulating friction with the object—to minimize risk of scraping)implemented using an extension of the velocity limiting algorithm;joystickRhoLimitScale may be set to 0.0 if a maneuver would cause thevessel to increase in incursion, but also decrease gradually from 1.0(perpendicular) to 0.0 (parallel) depending on how close-to-parallel avelocity demand vector is with a particular bumper region containing anobstacle.

Where applicable, various embodiments provided by the present disclosurecan be implemented using hardware, software, or combinations of hardwareand software. Also where applicable, the various hardware componentsand/or software components set forth herein can be combined intocomposite components comprising software, hardware, and/or both withoutdeparting from the spirit of the present disclosure. Where applicable,the various hardware components and/or software components set forthherein can be separated into sub-components comprising software,hardware, or both without departing from the spirit of the presentdisclosure. In addition, where applicable, it is contemplated thatsoftware components can be implemented as hardware components, andvice-versa.

Software in accordance with the present disclosure, such asnon-transitory instructions, program code, and/or data, can be stored onone or more non-transitory machine readable mediums. It is alsocontemplated that software identified herein can be implemented usingone or more general purpose or specific purpose computers and/orcomputer systems, networked and/or otherwise. Where applicable, theordering of various steps described herein can be changed, combined intocomposite steps, and/or separated into sub-steps to provide featuresdescribed herein.

Embodiments described above illustrate but do not limit the invention.It should also be understood that numerous modifications and variationsare possible in accordance with the principles of the invention.Accordingly, the scope of the invention is defined only by the followingclaims.

What is claimed is:
 1. A method comprising: receiving docking assistparameters from a user interface for a mobile structure and perimetersensor data from a perimeter ranging system mounted to the mobilestructure; and determining one or more docking assist control signalsbased, at least in part, on the received docking assist parameters andthe received perimeter sensor data.
 2. The method of claim 1, whereinthe determining the docking assist control signals comprises: receivingan occupancy map corresponding to an area about the mobile structure;receiving a mobile structure perimeter corresponding to the mobilestructure; and generating a limited velocity demand based, at least inpart, on the received docking assist parameters, the occupancy map, themobile structure perimeter, and the virtual bumper thickness.
 3. Themethod of claim 2, wherein: the occupancy map comprises a set of worldpositions corresponding to at least one object detected within theperimeter sensor data; and each world position in the set of worldpositions of the occupancy map represents a closest approach distance ofthe at least one object relative to a center of the mobile structure andwithin a selected azimuth range.
 4. The method of claim 2, wherein: themobile structure perimeter comprises a two dimensional planar figure orvessel polygon comprising a set of connected line segments representingan extent of a perimeter of the mobile structure.
 5. The method of claim2, wherein: the received docking assist parameters comprise a rawvelocity demand corresponding to a thrust demand generated by a thrustcontroller of the navigation control system; and the limited velocitydemand comprises at least one velocity component that is reduced inmagnitude and/or reversed in direction relative to a correspondingvelocity component of the raw velocity demand.
 6. The method of claim 2,wherein the generating the limited velocity demand comprises: generatinga set of world segments corresponding to and/or linking world positionswithin the received occupation map; determining a linear vesselprojection incursion distance for each perimeter point of a virtualbumper perimeter corresponding to the received mobile structureperimeter based, at least in part, on the generated set of worldsegments; and determining a linear world projection incursion distancefor each world position of the received occupation map based, at leastin part, on the virtual bumper perimeter; wherein the limited velocitydemand is based, at least in part, on a minimum of the determined linearvessel projection incursion distances and the determined linear worldprojection incursion distances.
 7. The method of claim 2, wherein thegenerating the limited velocity demand comprises: generating a set ofworld segments corresponding to and/or linking world positions withinthe received occupation map; determining a radial vessel projectionincursion distance for each perimeter point of a virtual bumperperimeter corresponding to the received mobile structure perimeterbased, at least in part, on the generated set of world segments; anddetermining a radial world projection incursion distance for each worldposition of the received occupation map based, at least in part, on thevirtual bumper perimeter; wherein the limited velocity demand is based,at least in part, on a minimum of the determined radial vesselprojection incursion distances and the determined radial worldprojection incursion distances.
 8. The method of claim 2, wherein: thedetermining the docking assist control signals comprises receiving avirtual bumper thickness and generating a virtual bumper perimeterbased, at least in part on the received virtual bumper thickness and thereceived mobile structure perimeter; and the generating the limitedvelocity demand is based, at least in part, on the virtual bumperthickness.
 9. The method of claim 1, further comprising: generating adisplay view based, at least in part, on received docking assist controlsignals, an occupancy map corresponding to an area about the mobilestructure, and/or a limited velocity demand based, at least in part, onthe received docking assist parameters, the occupancy map, and/or amobile structure perimeter corresponding to the mobile structure; andrendering the display view via the user interface.
 10. The method ofclaim 1, further comprising: providing the one or more docking assistcontrol signals to a navigation control system for the mobile structureto maneuver the mobile structure to avoid a navigation hazard detectedwithin the received perimeter sensor data.
 11. A system comprising: alogic device configured to communicate with a user interface and aperimeter ranging system mounted to a mobile structure and to providedocking assist for the mobile structure, wherein the logic device isconfigured to: receive docking assist parameters from the user interfaceand perimeter sensor data from the perimeter ranging system; anddetermine one or more docking assist control signals based, at least inpart, on the received docking assist parameters and the receivedperimeter sensor data.
 12. The system of claim 11, wherein thedetermining the docking assist control signals comprises: receiving anoccupancy map corresponding to an area about the mobile structure;receiving a mobile structure perimeter corresponding to the mobilestructure; and generating a limited velocity demand based, at least inpart, on the received docking assist parameters, the occupancy map, themobile structure perimeter, and the virtual bumper thickness.
 13. Thesystem of claim 12, wherein: the occupancy map comprises a set of worldpositions corresponding to at least one object detected within theperimeter sensor data; and each world position in the set of worldpositions of the occupancy map represents a closest approach distance ofthe at least one object relative to a center of the mobile structure andwithin a selected azimuth range.
 14. The system of claim 12, wherein:the mobile structure perimeter comprises a two dimensional planar figureor vessel polygon comprising a set of connected line segmentsrepresenting an extent of a perimeter of the mobile structure.
 15. Thesystem of claim 12, wherein: the received docking assist parameterscomprise a raw velocity demand corresponding to a thrust demandgenerated by a thrust controller of the navigation control system; andthe limited velocity demand comprises at least one velocity componentthat is reduced in magnitude and/or reversed in direction relative to acorresponding velocity component of the raw velocity demand.
 16. Thesystem of claim 12, wherein the generating the limited velocity demandcomprises: generating a set of world segments corresponding to and/orlinking world positions within the received occupation map; determininga linear vessel projection incursion distance for each perimeter pointof a virtual bumper perimeter corresponding to the received mobilestructure perimeter based, at least in part, on the generated set ofworld segments; and determining a linear world projection incursiondistance for each world position of the received occupation map based,at least in part, on the virtual bumper perimeter; wherein the limitedvelocity demand is based, at least in part, on a minimum of thedetermined linear vessel projection incursion distances and thedetermined linear world projection incursion distances.
 17. The systemof claim 12, wherein the generating the limited velocity demandcomprises: generating a set of world segments corresponding to and/orlinking world positions within the received occupation map; determininga radial vessel projection incursion distance for each perimeter pointof a virtual bumper perimeter corresponding to the received mobilestructure perimeter based, at least in part, on the generated set ofworld segments; and determining a radial world projection incursiondistance for each world position of the received occupation map based,at least in part, on the virtual bumper perimeter; wherein the limitedvelocity demand is based, at least in part, on a minimum of thedetermined radial vessel projection incursion distances and thedetermined radial world projection incursion distances.
 18. The systemof claim 12, wherein: the determining the docking assist control signalscomprises receiving a virtual bumper thickness and generating a virtualbumper perimeter based, at least in part on the received virtual bumperthickness and the received mobile structure perimeter; and thegenerating the limited velocity demand is based, at least in part, onthe virtual bumper thickness.
 19. The system of claim 11, wherein thelogic device is configured to: generate a display view based, at leastin part, on received docking assist control signals, an occupancy mapcorresponding to an area about the mobile structure, and/or a limitedvelocity demand based, at least in part, on the received docking assistparameters, the occupancy map, and/or a mobile structure perimetercorresponding to the mobile structure; and render the display view viathe user interface.
 20. The system of claim 11, wherein the logic deviceis configured to: provide the one or more docking assist control signalsto a navigation control system for the mobile structure to maneuver themobile structure to avoid a navigation hazard detected within thereceived perimeter sensor data.